URL shorteners have become more and more prominent in recent years because of shortening services such as "goo.gl" and "bitly."
The increased prominence of these shorteners is associated with the rise of social web, and most specially micro-blogging services like Twitter. This wasn't a huge issue for search engine optimizers, though, since Twitter and other social sdata was almost entirely disregarded by search sites - until recently.
As social search has become more important, so has understanding how SEO works for shared links. In a new Google Webmaster Help video, Google’s Matt Cutts explains exactly how the shortened URLs are treated. Cutts states that almost all shorteners are going to use a “301 permanent redirect” to move the page to the appropriate destination, and that Google will treat any links to that 301 redirect as being a link – for the sake of pagerank – to the destination.
That destination page will also receive the “social promotion” bump for any friends/followers of the original tweeter. Additionally, any other SEO data (such as anchor text, position on the page, and so forth) will be passed on. Cutts is quick to remind us, though, that a lot of additional rules apply in the world of social search. For one, most core pages on sites like Twitter have nofollow tags on any outgoing links. That doesn’t mean that the links are irrelevant, though. Beyond Google’s own social promotion, Cutts states that the links may be found in other pages – such as data feeds – where they will pass on link juice. [via Google Webmaster Help Channel]