Googles #1...

PageRank is one of the methods Google uses to determine a page’s relevance or importance. A high Page Rank makes you look like your site is an "expert" in it's field.

Any business worth their salt will want to be high on the google rank but this is not an easy feat. Some companies employ people whose whole job is to keep their company high on the google rank. The whole idea of being in the top 3 is that you are way more likely to get clicked on and attract attention and possible customers to your page. Some companies arnt up to the challenge so they pay Google to insert their ad on the page of a relevant search. These ads appear above and to the side of the "organic" or free listings. Google will be paid a small sum of money any time these paid listings are clicked on. I don't know about anyone else but I for one have never clicked on a paid listing. For some reason I just don't trust them. If their company or product is so great then should it not be able to make it onto the organic listings???