There has been a lot of talk recently about URL shorteners ever since the DiggBar was released. While reactions to the DiggBar are mixed I do have some concerns over the use of frames. I remember creating websites using frames and some of the problems it created. I am also surprised at some of the lack of thinking that went behind the DiggBar. It was only after it was released that they started to think about how the DiggBar passes link juice to the sites it frames, not to mention the extra pages that were being indexed as Digg content instead of the actual sources.
For some great reading on URL shorteners there is an excellent post by Danny Sullivan over on Search Engine Land. He covers all of the major URL shorteners and the features they offer. The post is everything you wanted to know about URL shorteners but were afraid to ask.
I have started using Bit.ly for most of my shortened URL’s on Twitter. It gives me some basic statistics about how often the link is clicked. I am not entirely convinced that the click count is accurate on Bit.ly, since website statistics does not match the number of clicks that Bit.ly usually says clicked through. Usually the traffic is roughly half of what Bit.ly says. That aside though Bit.ly does offer a 301 redirect instead of a 302 redirect so there is some like credit that can pass through the link. It might not make a difference on Twitter since all the outgoing links are nofollowed, but there are other sites that pick up tweets and links from Twitter that do not add nofollow.
When do you use URL shorteners? What one is your favourite and why?