Remember:US Code Title15, Chapter22, Subchapter III, ss1125,(d)(1)(B)(i)(IV). Fair use includes comparative advertising, comment, criticism, or parody, even where done for profit. Though quite honestly I doubt I'll turn a positive cash flow from this site :-)
Furtheremore, this ad is for a service unrelated to the business of the company discussed on this site, and as such, is completely non-competitive in nature.