Terms and guidelines that play a part in what Google determines are “good neighborhoods”:

Just like offline where knowing the right person can open doors – so can obtaining the right online link relationships.

While the exact Google algorithm is kept closely guarded; public patents and open communication from Google as to how they determine results to a query provide definite clues to follow when choosing whom to obtain a link from.

Here are some of these clues about the workings of the Google engine.

PageRank:

PageRank is the foundational aspect of the Googles engine.

If you care to read directly about it’s origins there are 2 papers that originally published by Googles founders Sergey Brin and Larry Page The Anatomy of a Large-Scale Hypertextual Web Search Engine and The PageRank Citation Ranking: Bringing Order to the Web. 

And while Pagerank is referred to in numerous applied and approved patents here is an original mention Patent #6,285,999

At a very basic level page rank is weighting system that gives a vote of credibility to a site or page as being a relevant source of information.

Page A links to Page B and Page B is given credit. How much value the link from page A to Page B gives comes from a variety of ever evolving factors such as how credible the source is on it’s own and how many links out there are on the page and the number of collective site pages.

There are very complex mathematical algorithms that serve to both balance and assess a source. For example. A site that has a high page rank on it’s own may not be passing it’s high page rank value to your page if the originating page contains hundreds of links. Every link on a page “dampens” the value of the link. This is due to the decreasing probability that any particular link on the page will be chosen by the searcher as they continue their quest for answers.

How you link your sites internal pages as well as how you organize the links coming into your internal pages (as well as how you choose what outgoing links to have on your site) is of high importance.

Here’s some mentions of link building importance by Google directly.

In general, webmasters can improve the rank of their sites by increasing the number of high-quality sites that link to their pages…

In  a recent interview by Eric Enge with Matt Cutts, Matt stated: “I would certainly say that the links are the primary way that we look at things now in terms of reputation.”

Pagerank is computed continuously and goes through numerous iterations before determining the PageRank value on a daily basis. This pagrank is put into the mix when determining displayed search engine results.

It is of importance to mention that the Pagerank that displays on the Google Toolbar is not the exact Pagerank of the site.

That feature is updated on a quarterly basis, more or less. It is a guide not the end all be all of the page or sites value. It does not show the complete picture.

It can’t.

The toolbar calculates pagerank on a scale of 0 to 10 while the actual system ranges in scores of billions. There is another Pagerank scale that also displays in the Google directory itself. This scale ranges from 0 to 7. The two PagRank graphical displays do not always match. Both of these pagerank toolbars provided by Google are gauges or indicators and not the actual determined daily page rank of a source.

When looking at Pagerank from the perspective of link building - Pagerank is simply an indicator of value a source has in backlinks. It is not the only determining factor in the engine results nor should it be the only determining factor in your link building strategy.

Just counting the back links a site has does not tell you the weight with which any given link is given. Straight from Matt Cutts:

“Do not assume just because you see a backlink that it’s carrying weight.”

This is true for the engines as well - a site with the most backlinks does not necessarily have the best response to a query. That has to be determined with other factors such as the text on the page, etc.

High pagerank increases the probability that a page may show up in top positions for a query but does not guarantee that it will.

Any site that links to another can pass page rank accept if the individual link or page metatag contains a nofollow in the metatag or link attribute. So for example a page that has a Noindex robots.txt  will keep that page from being indexed but it can still give value to the links on that page with pagerank if there is any to give. Redirects can also be followed for page rank according to a recent interview with Matt Cutts.

Google patent research shows that page rank is expanding to include other technology that will provide even more refined search results to the end user.

This is why sometimes you see high page ranks ranking lower in the engines and vice versa. There are also fluctuations in sites PageRank that are at times dramatic and impact engine results.

This has been referred to as  a “Google Slap”.

It is a time of transition in the search engine algorithms as they move towards semantic web and a more refined ways of matching queries with most relevant responses. The more integrity you apply to your marketing strategies the less likely you will be to experience any google slaps.