I am just coding the same thing right now (began a week ago). Also had the idea to use bit.ly as shortener (because of its api) and make use of multiple shortened links to store the data. Right before looking at HN I was doing some research for a good js compressing algo.
On the one hand i am a bit disappointed (that i am too late), but on the other hand hashify.me is made far better I could make it. Great realisation.