It can't just be back links.
"Backlinks are important when determining PageRank because Google sees it as a vote in the favor of the website. This is why quality links are important; not just any link will do. For example, if a tourist authority has a backlink to a website about destination weddings in that area, Google will regard this backlink, or 'vote' in much more high regard than if some guy's blog links to that site. On the other hand, if a highly ranked blog about travel links to that same destination wedding site, this can be viewed as a quality backlink as well.
Some webmasters take things a bit too far and assume that any backlink is a good one. This is not the case, and Google will actually penalize a website for linking out to one of the sites that they have deemed "internet garbage." Known link farms are a good example of this. Links to or from link farms can actually hurt a website?s PageRank, and in return hurt a website's visibility on the most important search engine, Google.
When determining the value of backlinks, Google looks at a number of things. They look at the link, the quality of the website that is linking to the site, the text around the link, and the anchor text (the underlined words that contain the embedded link on the website).
You Can't Fool Google!
The worst thing that a webmaster can do is try to fool Google. This is why sites are penalized when they are linked to by known link farms, or when they link to link farms. This is not quality linking, and it creates a flaw in the system when it comes to users. There are ways to get quality backlinks, and having quality content that establishes your site as an authority in its niche is one of the single most effective ways. If other webmasters or bloggers find that your site is useful, they will link to it. This is why Google counts a link back to a website as a vote in its favor as far as relevance is concerned."
http://www.ipagerank.org/articles/ba...importance.php
I can understand back link weight but thats a plus or minus but not the god factor in decision. Right now as it stands if you are looking for porn Google simply says look at these 3 tubes. Thats kinda bullshit.