AdSense is an advertisement application run by Google. Website owners can enroll in this program to enable text, image, and more recently, video advertisements on their websites. These advertisements are administered by Google and generate revenue on either a per-click or per-impression basis. Google beta tested a cost-per-action service, but discontinued it in October 2008 in favor of a DoubleClick offering (also owned by Google).[1]
Overview
Google uses its Internet search technology to serve advertisements based on website content, the user's geographical location, and other factors. Those wanting to advertise with Google's targeted advertisement system may enroll through AdWords. AdSense has become a popular method of placing advertising on a website because the advertisements are less intrusive than most banners, and the content of the advertisements is often relevant to the website.
Currently, AdSense uses JavaScript code to incorporate the advertisements into a participating website. If the advertisements are included on a website that has not yet been crawled by the Mediabot, AdSense will temporarily display advertisements for charitable causes, also known as public service announcements (PSAs). (The Mediabot is different from the Googlebot, which maintains Google's search index.)
Many websites use AdSense to monetize their content. AdSense has been particularly important for delivering advertising revenue to small websites that do not have the resources for developing advertising sales programs and sales people. To fill a website with advertisements that are relevant to the topics discussed, webmasters implement a brief script on the websites' pages. Websites that are content-rich have been very successful with this advertising program, as noted in a number of publisher case studies on the AdSense website.
Some webmasters invest significant effort into maximizing their own AdSense income. They do this in three ways:[citation needed]
- They use a wide range of traffic-generating techniques, including but not limited to online advertising.
- They build valuable content on their websites that attracts AdSense advertisements, which pay out the most when they are clicked.
- They use text content on their websites that encourages visitors to click on advertisements. Note that Google prohibits webmasters from using phrases like "Click on my AdSense ads" to increase click rates. The phrases accepted are "Sponsored Links" and "Advertisements".
The source of all AdSense income is the AdWords program, which in turn has a complex pricing model based on a Vickrey second price auction. AdSense commands an advertiser to submit a sealed bid (i.e., a bid not observable by competitors). Additionally, for any given click received, advertisers only pay one bid increment above the second-highest bid.
History
The underlying technology behind AdSense was derived originally from WordNet, Simpli (a company started by the founder of Wordnet, George A. Miller), and a number of professors and graduate students from Brown University, including James A. Anderson, Jeff Stibel, and Steve Reiss.[2] A variation of this technology utilizing WordNet was developed by Oingo, a small search engine company based in Santa Monica founded in 1998 by Gilad Elbaz and Adam Weissman.[3][4] Oingo changed its name to Applied Semantics in 2001,[5] which was later acquired by Google in April 2003 for US$102 million.[6]
AdSense for Feeds
In May 2005, Google announced a limited-participation beta version of AdSense for Feeds, a version of AdSense that runs on RSS and Atom feeds that have more than 100 active subscribers. According to the Official Google Blog, "advertisers have their ads placed in the most appropriate feed articles; publishers are paid for their original content; readers see relevant advertising—and in the long run, more quality feeds to choose from."[7]
AdSense for Feeds works by inserting images into a feed. When the image is displayed by a RSS reader or Web browser, Google writes the advertising content into the image that it returns. The advertisement content is chosen based on the content of the feed surrounding the image. When the user clicks the image, he or she is redirected to the advertiser's website in the same way as regular AdSense advertisements.
AdSense for Feeds remained in its beta state until August 15, 2008, when it became available to all AdSense users.
AdSense for search
A companion to the regular AdSense program, AdSense for search, allows website owners to place Google search boxes on their websites. When a user searches the Internet or the website with the search box, Google shares any advertising revenue it makes from those searches with the website owner. However the publisher is paid only if the advertisements on the page are clicked: AdSense does not pay publishers for mere searches.
AdSense for mobile content
AdSense for mobile content allows publishers to generate earnings from their mobile websites using targeted Google advertisements. Just like AdSense for content, Google matches advertisements to the content of a website — in this case, a mobile website.
AdSense for domains
Adsense for domains allows advertisements to be placed on domain names that have not been developed. This offers domain name owners a way to monetize domain names that are otherwise dormant. Adsense for domains is currently being offered to some users, with plans to make it available to all in stages.
On December 12, 2008, TechCrunch reported that AdSense for Domains is available for all US publishers.[8]
XHTML compatibility
As of September 2007, the HTML code for the AdSense search box does not validate as XHTML, and does not follow modern principles of website design because of its use of
- non-standard end tags, such as
and
,
- the attribute
checked
rather thanchecked="checked"
, - presentational attributes other than
id
,class
, orstyle
— for example,bgcolor
andalign
, - a table structure for purely presentational (i.e., non-tabular) purposes,1 and
- the
font
tag.2
1: using a table structure for unintended purposes is strongly recommended against by the W3C[citation needed], but nevertheless does not cause a document to fail validation — there is currently no algorithmic method of determining whether a table is used "correctly" (for displaying tabular data or for displaying elements, that get proportionally wider or narrower when browser window resizes in width without active client side scripting).
2: the font
tag is deprecated but does not fail validation in any XHTML standard.
Additionally, the AdSense advertisement units use the JavaScript method document.write()
, which does not work correctly when rendered with the application/xhtml+xml
MIME type. The units also use the iframe
HTML tag, which is not validated correctly with the XHTML 1.0 Strict or XHTML 1.0 Transitional DOCTYPEs.
The terms of the AdSense program forbid its affiliates from modifying the code, thus preventing these participants from having valid XHTML websites.
However, a workaround has been found by creating a separate HTML webpage containing only the AdSense advertisement units, and then importing this page into an XHTML webpage with an object
tag.[9] This workaround appears to be accepted by Google.[10]
How AdSense works
- The webmaster inserts the AdSense JavaScript code into a webpage.
- Each time this page is visited, the JavaScript code creates an IFrame with a
src
attribute set to the page's URL. - For contextual advertisements, Google's servers use a cache of the page to determine a set of high-value keywords. If keywords have been cached already, advertisements are served for those keywords based on the AdWords bidding system. (More details are described in the AdSense patent.)
- For site-targeted advertisements, the advertiser chooses the page(s) on which to display advertisements, and pays based on cost per mille (CPM), or the price advertisers choose to pay for every thousand advertisements displayed.[11] [12]
- For referrals, Google adds money to the advertiser's account when visitors either download the referred software or subscribe to the referred service.[13] The referral program was retired in August 2008.[14]
- Search advertisements are added to the list of results after the visitor performs a search.
- Because the JavaScript is sent to the Web browser when the page is requested, it is possible for other website owners to copy the JavaScript code into their own webpages. To protect against this type of fraud, AdSense customers can specify the pages on which advertisements should be shown. AdSense then ignores clicks from pages other than those specified.
***Information taken from Wikipedia.
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