The data dumps of Stack Overflow, Super User, Server Fault, their meta sites, and Web Applications are available for analysis on http://odata.stackexchange.com/. According to this blog post, Stack Apps should be available as well, but I don't see it there.
Looking at http://stackexchange.com/sites, there are a number of other pages which have the same status as Web Applications and Stack Apps. E&R is still in beta, but isn't all that far behind (especially because it was seeded with content from Chiphacker).
I'd like to have access to the data dump through odata.stackexchange.com to help answer questions like this one. What's the timeline for this operation?