I'm a little late to the conversation here, sorry, but I think it's worth pointing out the Common LaTeX Service Interface (CLSI). This is an open source API that I developed with Bobby Soares and it powers the online editors ScribTeX, ShareLaTeX and LaTeXLab (in a slightly different implementation). I've been pushing for a wider adoption of this at every opportunity since I think the benefits of an open standard are significant.
The idea is that anyone can access a LaTeX compiler online without worrying about setting it up and maintaining it themselves. On the other side, anyone is free to host the CLSI themselves and provide access to a LaTeX compiler. My implementation serves as a default standard at the moment, but I'd like to see the standard grow and mature with input from the rest of the community, and hopefully for other implementations to pop up. As more and more services are making use of LaTeX online, it would be nice not to end up with a fractured set of half solutions.
I'm part of ShareLaTeX at the moment, and we could provide access to our CLSI farm if needed.