A while ago I created a pipe to transform short URL's in their longer versions. However the pipe itself was rather complicated and required a modification for each new service to be supported.
Luckily, on the Network Security Blog I saw the link to LongURL, which provides the same action for multiple services (in fact I think that they fetch the URL with something like cURL and observe the final destination, so in theory they should be able to support any service) and they provide a REST API. W00t!
So, I created an updated, simplified version of the DeShortify pipe and modified my Twitter Content pipe to use this instead (if you currently us the Twitter Content pipe, there is no need to change anything at your end).
PS. This service doesn’t support Shrinkster.com, presumably because they show a click-trough page, rather than sending a 3xx header. I can’t support them with a custom pipe either, because their tracking page needs a POST rather than a GET, and it is also based on the ASP viewstate (so you would need to do a rather complicated dance of fetch the page, get the viewstate and repost it). Offtopic rant: this is what you get for trying to create the “VB 6.0” illusion on the web Microsoft! No leaky abstractions please!
Picture taken from [niv]'s photostream with permission.