Tinyarro.ws: tiny URLs get even tinier
Not only is the base link down to three characters and a dot -- ???.ws -- but Tinyarro.ws also saves space after the slash. For example, http://???.ws/??? is the shortened link to Download Squad. I'm not claiming that I know how to type any of those unicode characters, but that's probably not a huge drawback, because tiny links mostly get copied and pasted. As far as competing with other bookmarking sites on features, this one lacks any kind of traffic tracking, but it does have a bookmarklet and custom URLs.