[apowell]

Perhaps you could work with some of the classified sites themselves (start with smaller ones) to add an "Organize My Search" widget. Pitch it as a way for them to increase engagement and drive more return visits.

Also, many car enthusiast forums have "Cars for Sale" sections, and they're utter disasters. It would be valuable to be able to save those listings easily (bookmarklet?). A little word-of-mouth campaign on a forum can go a long way, and you can kick it off with a forum sponsorship with commercial posting rights.

(Side Note: The question in your header is implied -- don't state it, just answer it.)

[oms2010]

Yeah, I was thinking about the car forums approach actually, but the widget idea is a good too. Thanks for the feedback.