Very interesting. I find it laughable when I'd go to interview potential lead companies who claimed the quotes for search-engine driven yet they don't show up on a search. While on the phone with them I'd say "Ok, I'm on Google....where are you?"
You can type in "health insurance quotes" in Google and see who shows up on the first page. I see Hometown Quotes, Netquote and InsureMe.
The rest of the lead companies who can't afford to be placed in the 1st page of a Google search and using a wide variety of lead generate tools - all of which are 10 times less effective then key word searches.
Now the problem with key word searches is the cost per click is so insane they must find ways to basically sell leads to anyone and everyone. All of these companies have deals to re-sell leads to other places like leadsclearance and other "wholesale" lead dumping sites.