Like you, I'm worried about building something on a proprietary protocol. One company having control means they can arbitrarily deny you access if they don't wa

Like you, I'm worried about building something on a proprietary protocol. One company having control means they can arbitrarily deny you access if they don't want competition on a particular feature set, for example. Having said that, it hasn't stopped people building lots of Facebook and iPhone apps... For what it's worth, I have a service that archives people's tweets and lets them export to CSV (for reference/searching/stats, whatever). I plan to make a little bit of money off it generating nicely-formatted PDFs of tweets and pushing them through to lulu.com to be sold as paperbacks - a lot of people seem keen on the idea. We'll see how it goes.