There are a number of questions on Meta about whether it is OK to sponsor a competing product and the answer seems to be that this is acceptable. What happens if the owner of a trademarked name finds a competitor is sponsoring the tag for their product using the trademarked name? When this happens with domain names, social networking account names and many other situations online and in meatspace, the owners have recourse to claim the names. Is there any recourse here for that situation?
In particular, if a trademarked name draws a lot of traffic then by definition the trademarked name has value. If the value of that name is then used to generate revenue for SO and/or a competitor of the trademark owner, and to the detriment of the trademark owner, that would seem to be skirting the line of trademark infringement. There is a principle that in order to maintain ownership of a trademark one must defend it against infringing uses so, if in fact this can be seen as infringement, the policy of allowing sponsorship of competitive tags is just trolling for lawsuits.
Presumably, this legal issue will have been reviewed thoroughly and Jeff isn't really "trolling for lawsuits." That'd be just crazy. So I'm guessing there's a policy about trademark owners reclaiming tags sponsored by competitors, but if the answer is posted it's been evading my searches.