Probably a noob question. I see in the link building service section some services that charge you $20-$30 dollars per high PR link. I'm just looking into Scrapebox and I see you can harvest the shit out of URLs, sort them by page rank, see which ones you're able to post on, and you're left with some high page rank sites (4 or 5 pr) that you can leave a blog comment on. So if you can do this in a few seconds, why would anyone pay that kind of money for PR links? My guess is maybe a link on the main part of the site is worth higher than a blog comment link? Am I right?