Yahoo! Search Marketing will no longer allow advertisers to bid on trademarked keywords from other competitors beginning next week (March 1st, 2006). Resellers and non-competitive information sites will still be allowed to bid on the keywords though if they meet certain conditions, according to ClickZ.

Yahoo has been doing more and more work to attract big brand advertisers to link non-search campaigns back to search. The problem is, that means other competing brands can capitalize on this traffic.

Google has placed the restriction to disallow trademark keywords bidding since 2004. No trademark keywords should appear in the text ads.

Sources: ClickZ News, Search Engine Watch.