Don't know if this has been discussed yet or not, but you can get the #1 listing on Teoma through Overture by signing up for the REFINED keywords on overture. For example, if you search for SEO on Teoma, the first listing to come up is an Overture listing with a $2.72 bid. If you look to the right where you REFINE your search, and click on the first one which is "Search Engine Optimization", you will get a new list of results. If you sign up in Overture for the following phrase "Search Engine Optimization SEO" you would be listed on top. the #1 bid on overture now for this phrase is .05 cents.
Pretty cheap compared to $2.72, and i bet a lot of people will click on the REFINED choices!
Where it really works good is in situations where they didn't search for exactly the right term and they notice the REFINED results has what they were looking for. The percentage could be pretty high in this situation.