selling sites

I've read quite a few threads on how some members build up really good authority sites and sell them for 6 figures. My question is, where do you find these buyers? Are they the same guys who advertise? What do you typically have to show them in order to convince a sale (i.e.; web traffic...

Hi, i have been burned a few times now. And wanted to see if you guys know someone that sells decent adsense sites that you can actually make some money from. I'm a newbie and would prefer seo included. If not included, what service would you recommend? Thank you.