brinked - 8:06 pm on Mar 1, 2010 (gmt 0)
What I have seen, is on a popular link selling forums, many webmasters list links for sale on their sites. The link sellers who are not very experienced, post there websites in the post. While browsing through old WTS posts, the webmasters that have posted there URL in the OP, all have PR0. Is it possible that google has this forum under watch and is removing PR from websites selling links there?
If so...it would be so easy for a competitor to post a WTS ad and post a competitors website, therefore removing a competitors PR.