FAQ of advertising

The Web, including Adsense democratizes advertising, but it is a professional tool made available to all webmasters, making this FAQ indispensable. Indeed there are concepts to understand and mistakes to avoid when using a program of advertising, to make more revenues and ensure that the account is not disabled...
The information below was taken from blogs of Google, various forums and personal experience.

1. How many visitors must I have to use Adsense?
   It should be known that a click on a Adsense advertisement pays on average between 10 and 50 cents (occasionally it can pay a lot more).
   In addition one can expect a click for 200 to 300 prints of an advertisement, depending the subject of the site, and it seems that the number of prints reported by Google is lower than the number of visitors.
   Thus with 1000 visitors per day one can expect to gain around 30 dollar a month, but that depends on the topic of the site and its quality. In this case there will be a payment every four months.
   In addition, you are more lucky to be banished from the program with a smaller number of clicks by month. I would say that 1000 visitors per day is a minimum to start an Adsense program. This is my opinion, this is not official.
2. What is a contextual advertisement?
   It is an advertisement that is selected when its contents, the promoted products, is connection with the contents of the page.
   Adsense is contextual. Ads are selected according to the keywords in the page where the user put the code. The more the ads is related to the page, the higher is the incomes.
3. Do I need to tell the advertiser that I put ads on my pages?
   It is totally unnecessary. The JavaScript ads you place in your pages contact Google, which in turn analyzes the page and select the most relevant ads for the content of these pages.
4. What is it exactly, an incentive to click?
   Inciting to click, this is when visitors are requested to click not for the product, but to help the webmaster to make money! Incentive are message as "I need money, please etc..." or even an image just beside the ad to let visitors believe the ad is the link for the image! And also when the ad may be confused with the rest of the page.
   It is not an incitement when the page describes a product that could appear through an ad, since the visitor that clicks does know the product, and thus is a potential customer!
5. Can I click on an advertisement to test the system?
   Definitively not. Google put at your disposal a set of tools to test your advertisements without risk that your account is closed for invalid clicks.
   This test system not only makes it possible to click on advertisements which are presented to you, but also on those which are presented to other net surfers, in foreign countries. It will inform you thus if it is profitable to insert advertisements on a given page.
   I you have clicked on an publicity accidentally, you should not send a message to Google to inform it of that, as it is specified in its blog.
6. How does the advertiser detect fraudulent clicks?
   Google uses hundreds of criteria to identify the fraudulent clicks, the complete list remains secret but some indications were given to reassure advertisers. That relates to the clicks with the webmaster or the entourage and the Trojan horses that infect a website.
   A first level filtering is applied by a robot to all clicks. Geographical area, navigator, IP address, these criteria detect 95% of the prohibited clicks which are then deducted from incomes (and invoice of the advertiser of course).
   On a second level, suspect sites are studied closely. Here, advertisers are involved. Google signal abnormal activity to them, the advertisers can then ask ro nullify certain clicks, which leads Google to inspect the site and to possibly desactivate the Adsense account.
   Finally, the advertisers can signal themselves the abuses.
7. Ads are they paid links?
   Paid links are prohibited by the TOS (Term of service) of search engines. But ads are not themselves a sort of paid link?
   Actually no, because what is forbidden by the rules, is the manipulation of the algorithm by paying links on pages with high PageRank, to transmit it to the site of the buyer of the link. But  ads actually are blocks of JavaScript code that redirect  on the advertiser's site, they therefore have no effect on PageRank (we suppose that Google is able to recognize an advertiser).
8. The more I have visitors, and the more income drop!
   This is something which is often noted. This is not have anything abnormal because the advertisements whose income by click is highest are also more rare ones. By increasing the number of displays and the number of pages, one so collect advertisements which have a lower revenue.
   In addition, the price of an advertisement depends on the relevance of keywords of the advertisement with the contents of the page, and this the increase in the traffic should not be obtained by a disparity of topics in the site.
   It is necessary to reduce the number of advertisements posted to only keep most relevant ones and to maintain the value by click. See also at Smart Pricing.
9. I changed nothing on the site, but my incomes do not cease declining!
   The problem is there: when a site is inactive it receives advertisements which pay less. It seems that Google privileges active sites with new pages or even pages whose contents evolve.
   On the other hand, the number of clicks on advertising tends to decline overall. According to a study described on the site Adage, the number of clicks has been reduced by 50% over the last two years and in 2009 only 16 of surfers click on ads (less in recent years).
10. Why is aggregate number of clicks greater than the sum of channels.
    This can have several causes. Your pages can be replicated by other sites. Users can also click on ads on cached pages in search results.
11. Does a sitemap improve income from Adsense?
    The sitemap does not improve incomes directly.
    But creating an XML sitemap and registering it at Google can make it possible only to have a better indexed site. If search engines take into account the additions in the sitemap, new pages will be indexed immediately and as said above, Adsense likes new pages.
12. How to increase my income?
    It is possible to increase the number of clicks by a better placement of ads: preferably at top and on the left of the page. If the content is short, the ad should be placed after the text. If it is long, put it inside.
    Google gives advices on placement of advertisements.
    Very often, the fact of creating new pages increases income.
    The pages treating of actuality have good income, but it is necessary they are indexed quickly, which takes place on continuously developed sites, because engines adapt themselves to the their activity.
    The value of the advertisements is in relation to the keywords of the page and with the request on those. The relationship between supply in keyword and demand determines the value of advertisements.
    Choose a filename in connection with the contents, this can have an immediate effect by improving the relevance of the advertisements, just as internal links by the wording or the contents of the <title> tag.
13. Are incomes linked to PageRank?
    That was sometimes brought back. A site having a PR of 6 or 7 would receive advertisements of higher income. But there is nothing official with that. It can be an indirect effect, because the choice of the advertisements depends on the links on the page.
14. Can I to put images beside Adsense ads?
    Google recently decided to clarify its position relating to images, and about texts which resemble to Google advertisements.
    One should not place images near ads so that one can think that the advertising link has a relationship with the image.
    One should not either have text resembling an advertisement.
15. What is the number of page impressions?
    A page impression is generated each time a page is loaded that contains one or more ad groups or link unit. This number is different of the number of displayed ads or ad units.
16. Is my account lucky to be disabled if my eCPM is too high?
    In fact, the question which should be raised is not: "Is My eCPM too high?" (eCPM = income by click) but rather: "Is My account profitable for the advertisers?".
    If one make use of various tricks to obtain more clicks and that leads to advertisers' sites visitors that don't know why there are here, this is not a good plan.
    The causes of disabling, apart fraudulent clicks are:
    1) The arbitration: consist in making a Adword campaign with low cost advertisements in favour of a site with weak content, but advertisements with high income (for example 1 cent the ad for Adword, 40 cents for Adsense!).
    2) MFA (Made For Adsense) website. The contents are non-existent or without interest, the pages are made only for clicks on the advertisements.
    There is actually a campaign from Google to suppress définitively all such accounts.
    On the contrary you should be an effective intermediary, and bring customers to sites which offer incomes to you. For that, ignore any method for increasing clicks such as full page advertisements, but write good and informative articles instead. Is there chance an account is disabled if Adword customers are satisfied?
    If by misfortune, in spite of a good behavior, your account is disabled, there is a lot of other less known advertising furnishers.
17. Can I be disabled for too few clicks?
    This has never been reported, but if there is very very few clicks, it is better to be careful not to make accidental clicks.
18. My CTR is very high. Will I be disabled?
    The CTR is sometimes very high on some sites. If you do not have done anything wrong (read the rules and what to avoid with Adsense), you do not hae the risk of being banned for that.
19. Can I appeal if my account is disabled?
    Under the terms of the contract, an account can be deactivated for any reason if Google sees fit. Editors are suppliers of space, Google, a customer can switch suppliers if it wishes.
    It has happened before a publisher to sue Google and he wins, in USA, this was the Greenspan case. In fact he did not get his account to be reactivated, but only the money gained and returned to publishers to be paid to him, $731. That because Google was not able to justify, at the trial at least, the reason of the deactivation.
    The judge's decision is debatable, however, as to give its reasons, Google should reveal some aspects of its algorithm, thus facilitating the work of fraudsters!
20. Can I look myself at my pages with my CPM ads?
    CPM ads are paid for the number of displays and not the number of clicks. However, it is not a problem to consult his site, even often. Google does not count your visits.
21. Does Adsense improve indexing of my pages?
    Google replies clearly no to the question. Page holding ads are analyzed by a robot named Mediapartner, while the search engine makes use of another program named Googlebot. Results from one are not used by the other.
22. What are sections?
    This is explained in the Google Adsense Help Center.
    You can include special comments in your HTML page that define sections of page to emphasize or to ignore. The code look as <!--google_ad_section_start --> and the content of the section is used to choose the ads.
    It must be large enough to make relevant ads.
23. What is Smart Pricing?
    Same contextual advertisements placed on the same site, but for different user accounts (that has been experienced) do not bring the same amount and the variation can be very important. That is in smart pricing.
    Google makes it possible to advertisers, providing they chose this option, to have a reduction on clicks when they come from an Adsense account where the visitors convert less, in other words buy less. If you bring to advertisers not very interesting visitors, your ranking drops at Google, and your site or all the sites of your account will pay less for same advertisements. Google obtains this information thanks to cookies placed on the sites of advertisers. The index of Smart Pricing is modified each week
24. How to get ads in video format?
    Google now offers videos ads that are of course, more likely to get hits that images. Unfortunately, it is not possible to select specifically this format. For such announcements, you must choose the format of image ads, then dimensions compatible with videos: 200x200, 250x250, 300x250 or 336 x280.
    Google warns that these ads are limited in number.
25. Is it better to place a single ad unit or several?
    It depends on the size of the text on the page. If the text is very long, many units may be inserted, otherwise a 300 x 250 rectangle is enough. Always check the relevance of ads, how they relate to the content. It is common to place a link unit and a contextual unit on each page.
26. What is the most profitable format?
    According to some users, a 300 x 250 rectangle is the best format. It may be embedded into the content, usually at right with text above and belong it.
    According to the head of Adsense at Google the best incomes come in order from:
    1) 336x280 rectangle.
    2) 300x250 medium rectangle.
    3) 160x600 skyscraper.
27. What are the higher ranking keywords?
    Keywords for which advertisers give the most money are: insurance, credit, real estate, house, car, hotels, cinemas, schools, digital. These words must be contained in a page with a relevant context.
28. What is a good CTR? A good eCPM?
    There is no predefined value, because it depends on the topic of the site, the number of ads which is an editorial choice. The CTR may be increased with a good integration. Most sites have a CTR between 1 and 5%.
29. Can I define the context for a contextual ad?
    For contextual ads, the context is the entire page and the ads are choosen according to keywords found in the whole content of the page. Sometimes, this is not desirable, and you would prefer delimit a part of the page to define the context and so choose the keywords.
    This may be done with some tags that are recognized by the robot that scans the pages.
30. Are statistics being displayed in real time?
    No, approximately every 15 minutes or a longer period. This can sometimes take hours.
31. Can I know which ads visitors have clicked?
    To do this we must define custom channels. You can not know clicks on announcement made by a specific advertiser.
32. Can I use a script statistics without problem?
    Yes, as long as the script does not change the code of the announcements.
33. How much can be gained with Adsense?
    Here are some examples of the bigger known profits:
    - DigitalPoint.com: $10.000 per month.
    A collaborative website publishing articles for webmasters.
    - AskTheBuilder.com: $30.000 per month.
    - Digg.com: $250.000 per month.
    For that they have 30 millions pages seen per day.
    Digg is a collaborative site of information, which selects articles according to a system such as that whose source code is given on xul.fr, and which allows readers to mark articles.
    - PlentyOfFish.com. Makes $300000 per month. It is a dating service with more than 15 millions pages views per day.
    These cases relate only to personal sites, with one or some people for management and do not include networks of sites. Google has a page about success stories with Adsense.
    These amounts are confirmed by Google for most of them. Take note than previously I had another website at top of the list, but it has completely disappeared from the Web! The success may be ephemeral...
34. Why ads do not appear only on my computer?
    This comes from the state of your system. To clean it, delete cookies, launch an program against viruses.
35. Why do I have only PSAs?
    There are many possible reasons. Among other things, access to robots is blocked by robots.txt, or a login with a password, or the pages do not have enough content or content prohibited, or the type of ads is not enough varied (images only). Anything that makes the Mediapartner robot was unable to crawl the pages, or it can not find ads for the content.
36. Can I put Amazon ads on the same page as Adsense ads?
    This is allowed.
37. Could a cracker steal my earnings?
    This happens from time to time, a hacker can find a way to access your site and replace the code of your ads by his own. The script Adsense Checker can detect this type of hack.
38. Can I put ads on a parked domain?
    This was permitted only through a specialized service, Adsense for domain, in this case, ads were choosed according to the name of the domain. But it was shut down in June 2012. It is forbidden to put ads on a empty page.
39. What percentage is shared with the webmaster which displays ads?
    Google gives 68% of revenue paid by the advertiser on AdWords to the webmaster who displays ads to the content, so contextual ads, and links.
    As for ads on pages of custom search engine, they report 51% to the publisher.
    Google plans to show in the future the percentages in the Adsense interface.
40. How to get a premium account?
    The premium account allows more freedom in applying the rules, but it is restricted to a limited number of publishers.
    Google is contacting the webmaster to offer him a premium account, it is useless to ask.
    It takes a certain amount of Adsense revenue or impressions. These numbers are not disclosed, it has been talked about a time of 20 million impressions per day.
41. Can I make money with Facebook and Twitter?
    The question was asked on the forum Webmasterword and opinions are somewhat mixed. Example:

    I have a Twitter account with 27,000 followers in 4 languages. When I publish a very important message from me the PDF that is linked receives 10 visitors.

    In general, a Facebook account can provide substancial traffic on condition that you spend enough time on it. Twitter brings traffic to a page if it is retweeted many times. In my experience that brings a minimal gain from ads.

42. Converting the site to HTTPS has it an impact on Adsense?
    You will see a net drop in revenues. Indeed, when a page goes SSL the entire contents must also respect this protocol, including advertising. Google must therefore find ads that are designed for this protocol and they are much less numerous than conventional ads. Also the old ad codes are not compatibles with SSL.
43. Should I limit the publication of the advertisements to my site(s)?
    It is possible from the setup panel to provide a list of sites that display ads, which prevents clicks on other sites.
    And contrary to all expectation, it is advantageous to do so. Because we could think that if the pages are copied from other sites with Adsense code, they can at least bring in income, but it is a mistake.
    Advertisers do not want their ads appear on any kind of site, so by limiting allowed sites, your account get their trust and ads that make more money. According to my experience.

How to know the effect of ad blockers?
If you use both Adsense and Analytics, the script below (provided by Webmasterworld's users) allows to know the number of ads loaded and compare to what is displayed in reports.

<script>
if(typeof adsbygoogle !== "undefined") {
  window.addEventListener('load', function() {
    if(typeof ga !== "undefined") {
      if(typeof adsbygoogle.loaded === "undefined") {
        ga('send', 'event', 'AdSense', 'Ads blocked', { "nonInteraction": 1 });
      } else {
        ga('send', 'event', 'AdSense', 'Ads not blocked', { "nonInteraction": 1 });
      }
    }
  }, false);
}
</script> 

You should know how to create a segment on analytics and assign the events generated by this script.

Adsense

Adsense tutorial - Ajax and Adsense - Thing to avoid - Adsense behaviors - Advertising FAQ