Google’s main source of revenue and advertising product is Google Adwords. In 2012, the total advertising revenues were $42.5 billion. Automatically, Google will determine the subject of the page and show relevant ads that are based on the advertisers’ keywords. Publishers of Adsense are able to select channels to direct Google’s ad placements on their pages. This helps increase the performance of their ad units. Ads come in all different types such as text ads, mobile text ads, in-page video ads, and image/banner ads. Yahoo! and Bing Ads are the main competitors of Google AdWords. There are search engine marketing agencies that offer account management to help clients with building AdWords accounts. There is also account management software provided by Google, called AdWords Editor. Since ads by Google are completely dependent on keyword selection. The choice of the keyword is very important, as it heavily impacts the level of exposure that the Google ad will receive and to who sees the ad.