To understand the relevance of Adsense one must learn its working.
A website is incorporated by the webmaster with a java script which pulls advertisements from the Adsense program every time the page is accessed. These ads should be related to the contents on that webpage. Each time a visitor clicks on an ad, the search engine gets paid by the advertiser and a portion of this money goes to the webmaster.
All the monitoring and payments for the ads are managed by the search engine which reduces webmaster’s job to mere choosing of targeted ads. Ads available in this program are unlimited. Thus the webmasters contently concentrate on the revenue area.
First reason why Adsense is important is that it provides ample options to webmasters and publishers to customize and format their ads according to the appearance and layout of their website. Thus suitably displayed ads draw more attention from the visitors who might even inadvertently click on them.
Second reason is that Adsense allows the webmasters to track how their sites are functioning and enables them to monitor the performance of ads based on webmaster-defined channels, trends and contents. He can promptly make necessary changes with the help of real-time reporting provided by the program. It allows him to group web pages by URL, domain, and ad type that helps in sorting the pages on which ads perform well.
Third reason is that these targeted and content-sensitive ads have helped advertisers earn more profits. Adsense has achieved this by having the contents created and well maintained by other people.
Performance of targeted ads depends on well targeted contents. Hence maintaining the quality of contents written becomes an integral foundation. Initially webmasters and publishers were unaware of the economic potential of advertising opportunities their websites provided. Adsense has simplified the whole process and made them realize profits which came along with their site.