I'd say Kara's Adult Playground aka
http://www.karasxxx.com
It's been soooooooooo promoted and branded over the years that most surfers have seen it or heard of it.
It's still listed daily on big tgp's and untill recently was one of the first links on World Sex.
There's probably more forgotten non updated old sites with Karasxxx ads out there than most any other site in existence.