If you were to offer an self-hosted version that I could install in my own datacenter, that'd be of serious interest to me (my company). Allowing anyone else to hosting the sort of documents that end up in latex (very sensitive research papers) is simply not an option, but collaboration among researchers would be very convenient on a platform like this if we could control it. Sure, lots of latex is university or public research that ends up getting published anyway, so security is not a concern. A lot of it, however, is industrial research labs where information security is of paramount importance. This seems to be an overlooked market among many people who just want to make web programs. I urge you to consider the possibility that you have many potential customers who are not interested in letting you host their data.

Very cool site, though. Google docs for latex is a very useful offering. Thanks!