hi I am going to buy some backlinks from a guy that offers permanent backlinks on his blogrolls. the blogs are supposed to be PR3 and up. my question is, how do i make sure that these blogs are not worthless? for example, I could make sure PRs are not fake. I could make sure the domains are not deindexed. what else do I need to watch out for? is it possible that the blogs are worthless for some reason? what do i need to do to make sure these are legit backlinks and they are not worthless?