Based on a couple of posts in forums, there are dirty pages with fake PRs. This is how it works:

You receive an e-mail asking to do a link exchange from a PR 6-7 site. You visit the link they provide and notice something strange… a delay in showing the PR request, as if it’s being re-directed. Curious as to why that is, you do a quick search on Google for their URL, and you realize that the page doesn’t even come up in the search results.

Well, how can a site have a high PR but not even be listed in the Google Searches? Answer: FORGERY.

When receiving these types of requests, it’s always best to judge a site by the amount of traffic it receives, back links, and most importantly: content.

I won’t post the URL of the site as to not give it undeserved traffic. But for all those thinking of doing link exchanges… be careful!