is it a trademark violation to display PPC ADs of Competitors?

[yobo]

Curious to know if others have thoughts about this?

My particular situation is in Yahoo Shopping with their new CPC model.

In Yahoo Shopping, when you type in my trademark term my site is the first to come up and then there are a bunch of domain parks that display overture's xml feed results. In the "domain parked" results I turn up but so don't 100 of my competitors.

Is this a violation of trademark? Yahoo is blatenly profiting off my name by showing sponsors ads while I am not.

Curious to hear what others think about this situation.

[redzone]

There has been some precedence set, but it's mixed.

Playboy sued a few years before, in 2 seperate actions. One, against an SE, and the SE caved in. The other was against a former playmate, and she won in Court...

There are other's out there, easy to find.