URL shortening services have become more and more prominent in recent years with the rise of the social web, and most especially micro-blogging services like Twitter.
Originally, this wasn't an issue for search engine optimisers because initially websites such as Twitter and Facebook were disregarded by search sites. However, updates by Google on their PageRank algorithm now take into account the impact of social search and therefore have update their algorithm to reflect the importantance of understanding how SEO works for shared incoming links.
Google's Matt Cutts explains how shortened URLs are treated as a link to a given page, that is, typically the page is followed with a "301 permenant redirect" and so, for the sake of PageRank, the destination address is seen as having an incoming link. This link however receives a special type of "social promotion" including any friends or followers of the original source, whether that be via Twitter, Facebook, LinkedIn, Google+ etc.
Additionally, any other SEO data (such as the anchor text, postion on the page, and so forth) will be passed on and taken into account. However, Cutts also outlines how most social networking websites take advantage of the nofollow tags, as is seen on all Twitter links. Whilst this doesn't mean the links are irrelevant, the links may be found in other pages - such as data feeds - where they will impact the PageRank of a page.
Do you shorten your URLs for your blog articles on any social networking sites? You can get in touch with us by mentioning #ALJTMedia on Twitter or by leaving a comment on our Facebook, Google+ or LinkedIn page.