I've seen some of those sites and have done DD on one.
Can't speak about all of them, but the one I did DD on used a fraud technique that is rapidly increasing in popularity. The way it works, in a nutshell:
1) The seller sets up a random site with some Adsense units on it.
2) He then buys cheap traffic that is guaranteed to click through (against Adsense TOS) and a bunch of junk traffic to keep the CTR down.
3) To make it look like the traffic is actually organic, he forwards it through a redirect that spoofs the referrer so that it would show up in Analytics as organic traffic.
EDIT: Looks like there's now even a service for this here on BHW (
http://www.blackhatworld.com/blackh...etplace-google-exploit-pro-black-hatters.html). That's how simple it is for fraudsters to operate ..
4) They flog the site on Flippa quickly (typically 2-3 months) before Adsense bans it.
5) They keep the bought traffic flowing whilst the site is in Escrow so that the buyer can see that the site is indeed making money. Obviously, once cash has been released the traffic stops and the buyer can often also say goodbye to their Adsense account.
There are two things you can do here:
Firstly, remember that if it looks like a duck, swims like a duck, and quacks like a duck, then most likely it's not a swan.
Secondly, look up the main keywords that are claimed to bring traffic (in most of those cases the majority of the traffic is with a N/A keyword but you can just look at the most popular actual keyword to get an idea) in Google, see if the site ranks anywhere on the first page for these keywords and also see the search volume for those keywords. If those numbers don't add up then you're dealing with a scammer.
Also check the link profile of the site. It's highly unlikely that a site with 5 links ranks high enough to get tens of thousands of organic visits per month.
Bryan
