On Sites like Twitter.com it’s quite common to use a URL Shortening Service to reduce the Text length posted. Lot’s of this Services already exist, like tinyurl.com, is.gd, bit.ly just to name a few.
From the Users point of view it doesn’t make a big difference which one to use: some have bookmarklets, some have statistics for the generated links, but at all they simply shorten a URL.
From the Developers point of view (that Guys that have to integrate that Services into their Applications because Users requesting that kind of Features) different Services do make a difference!
In my honest Opinion there’s only one Service you really and you should use: bit.ly! They offer Statistics, they do have a bookmarklet, a Firefox Plugin, a mobile Version and even more Tools.
The big difference compared to most other available Services: they offer a proper API (that’s something developers rely on, when for example the Long URL for a shortened URL is displayed before you click on a short URL without knowing where it might take you to!).
So if you want Features in your Twitter Client stick to a good Service with a proper API just like bit.ly. Believe me, no Developer wants to come up with workarounds for other Services that pop up and that don’t have a proper API or any other Way to intergrate it into their Application.
A good Example might be the new German Site twiturl.de: They have an API some can use, but they simply missed the Function to turn a shortened URL back into a long URL. So no Twitter Client Application can display the long URL before you click on the short URL (which might redirect to some malicious site btw). Sure there also a way to obtain the long URL to display it, but it’s a real pain in the arse to integrate that using work-arounds and stuff.
So, if you want Integration and Features in the Twitter Clients you use, please stick to some good Service like bit.ly. Thanks
p.s.: i am aware that it’s quite easy to get the long url via a header request