GMChost.com Webmaster Guide

There have been a number of lawsuits where companies have sued and won after someone used their trademark or company name inappropriately in their meta tags. In fact, we nearly had to take competitors to court a couple years ago for blatantly using our better-known WebPosition brand name as a means to drive more traffic to their own site. It wasn't until we were on the verge of filing suit that they conceded.

Basically, there are laws regarding "fair use" of trademarks. If you are including competitors' brand names for the purpose of bringing in more traffic to your own site, then you're asking for trouble. However, if you are doing a "fair use" comparison between your product and a competitor's in the body text of your page, then your legal liability may not be so clear-cut. For a detailed listing of legal cases regarding trademarks and meta tags, see:

http://searchenginewatch.com/resources/legal.html

In general, your odds of getting into legal trouble go up much faster if you mention a trademarked name in an invisible area of your page like a meta tag. It's difficult to prove that inclusion of the keyword in the meta tag area was for any other purpose than to profit from another's brand name (i.e., to gain Web site traffic).