[nickherc]

Ranking in google is like popularity contest. For example, some blog finds your webpage interesting, they write an article in which there is a link of your homepage. That's backlink and it increases your reputation in google's eyes. The more you have that, the higher your page will rank.

You have dofollow and nofollow links. Dofollow links are the one that matter to google, nofollow links are good for traffic. It's good to have both of them, majority ofcourse dofollows.