I know I am probably going to get flamed for this post, but I tried to deny this for a long time. I have sites and seen sites that have plenty of PR5 and PR6 and even PR7 back links and their PR is Still 4 or lower. Now I found the perfect example that Relevant sites help with your PR. I was approving sites in my Directory and Ran accross a Fish market that sells Fish online . They are currently PR5 and have only 900 backlinks. Most backlinks are PR4 and lower and one Backlink is PR5 which comes from a Seafood Directory. The rest backlinks are Also or Most are Food related. so for all of you buying links on PR7 sites that have nothing to do with your website, SAVE YOUR MONEY!. Its not going to help with PR.. Maybe Serps IDK now.
I thought relevancy had nothing to do with PR... but I have to agree with you that there're plenty of websites out there with just a few hundreds of backlinks and they are PR4+. Back to your point, it's never good to buy links just for PR, even if it's pr 8+.
you can get back links from PR 7 or PR 8 sites that have absolutely no relevance your own site and still gain high PR ( for whats its worth ). The quality and authority of the PR 7 site linking to you is important.
I don't think people buy links to get their PR up. People buy links to boost their rankings in the search engines. That's what I think about buying links.
SRLee, in ideal world noone buys links just for PR but if you surf internet you will notice so many irrelevant links on high PR pages. Thus people buy high PR links, even irrelevant just to boost their PR and authority.
Yep i agree that links not only have to be of a higher PR but also relevant to your site to have any benefit. I think that google is getting better at screening out sites with bought links