I would like to know what are good reasons for me to use the "no follow" on my site?
As far as I know, using the "no follow" attribute only effects the page rank of the link I'm linking to, and not mine. I understand why using it is important in user generated content in order to fight spammers, but I can't understand the other reasons that make so much sites use this. Are there ways it can effect a web-site's rank if he linked to a site without a "no follow" attribute although he couldn't vouch for it? Is it just that he doesn't want to make others have better ranks?