Google Inc. and its Gmail e-mail service attempt to target advertising to users of the service by scanning their messages. Sometimes, the results are less than relevant, however. The concept of marketing products to Internet users on the basis of what they express interest in is not unique to Google. Many online firms target their advertising based on terms entered in a search engine or the Web sites they visit. Consumers have frequently noted the absurdity of some of the matches that arise from this technology. Google's Gmail advanced the concept by selecting ads on the basis of individual personal e-mail messages. Going through e-mail can provide a significant amount of information about a consumer, but it can also result in false and strange presumptions about what a user may want to purchase. Microsoft Corp. is testing a system similar to Gmail in its Windows Live Mail Desktop software. Users of the test version see advertising selected on the basis of their e-mail content. Other firms, including America Online and Yahoo! Inc., are not interested in using the e-mail scanning approach to target ads, however. Google receives money by charging advertisers every time a user clicks on one of their ads. Advertising firms bid against each other to have their ads displayed when specific terms appear in a search query. Sometimes, the Google matches are very accurate, but at other times, the results are laughable.