EDIT: Wow, a lot of action in this thread while I was typing! If cbp says he has run tests that show
PR is not "leaked" to pages that are linked to, I'll have to defer to him on that, I don't have any proof either way. I was just going on my understanding of the original
PR equation. Here's my original post anyway:
I agree with cbp, if you're going to exchange links with the specific intent of boosting your
PR, you'll want to do it with pages of similar or higher
PR on their links page. The reason being, if you have a
PR of 4 on your links page, you'll have no problem finding link exchange partners, and since you know you don't want too many links on one page (you'll look like a link farm) you'll want to save each page's "link real estate" for higher
PR link partners.
Did that make since?
Now, there's nothing wrong with exchanging links with sites with low
PR on their links pages, just realize you won't get as much of a
PR boost. I'm not sure of the context that Mel's quote came from, but if you are working specifically on boosting your
PR (and everything else is equal), a link from a high
PR page will help you more than a low
PR page.
When
I use the term "
PR leak", I'm talking about the inevitable passing of your page's
PR to any page you link to. Unless you use javascript links or other methods to prevent the googlebot from following your links, you will be "leaking" your
PR on to that linked page.
All that said, I really don't put too much stock in
PR, I certainly don't ignore it, but I don't worry about it too much.
I hope that answers your question, or at least gives you my opinion on the answer.