I was reading a blog today and it kept talking about the importance of having different types of links on your site. I understood the lingo about anchor links, etc. but then they started talking about PR1 and PR8 links, etc. and I had no clue what they are talking about. When I google the terms, all I find are sites selling PR links.

Can anyone help me out and tell me what they are and why I might want/or don't want them?

THanks.