[SEOBSDetector]

Here's one that is a little under the radar. The Young Entrepreneur's Council theyec.org posts guest blog articles on well known sites like Forbes, Inc, B2C. Those articles are full of "expert" quotes from members of the YEC with paid memberships - all with links to their sites of course. You'll see the same sites linked to in most of these mostly useless articles. You won't be seeing any quotes or links from people who haven't paid the YEC. Nice little link exchange to get links from really prominent sites.