Over the years, our good friends over at Google (largely through the input of Matt Cutts through his webmaster Q&A videos), we’ve heard a lot of information about the best ways to optimize sites for Google. While there are plenty of other opinions (even those contradicting data provided by Cutts and other Googlers), these official statements give a good demonstration of Google’s priorities; even if there’s a way to avoid the concept presented in these videos, the alternatives are usually “gamed” results, and short-lived. That doesn’t mean there’s no room to question, however. One of the big debates is over how to get link juice from one page to another.
While there are dishonest ways to try to use this (directing all link juice to various site pages to a specific page), the primary purpose is to ensure that duplicate (or very similar) content on a site has its inbound links counted toward a single page. There are three core methods of passing link juice, each with advantages and disadvantages.
First is simple page architecturing for your site. With proper planning, you can create a site that has no duplicate content. Even dynamic pages can be displayed on a single, static URL. However, there are many limitations – and architecturing can’t do anything to help you in a site move, page title revamp, or other similar changes.
The second solution is to use 301 redirects. This is where a big debate erupts. What we know is that Google does pass on link juice from the original page when a 301 redirect is used. Even items like anchor text are included. But previously released information has stated that Google doesn’t necessarily pass all link juice from 301s – a contradiction to statements made in years past. The most current information, however, is that Google is passing along all link juice (“not guaranteed,” says Cutts, but certainly Google’s aim).
And as a final alternative, you can use a canonical rel= tag. Far more than the 301 redirect, however, this option is risky. Matt Cutts has stated that, while Google does try to group inbound URLs to a site through to the appropriate canonical address, it’s far more effective to use 301s.
[for additional resources, look to Google Webmaster Tools and the Webmaster Help Channel]