Could we add a feature to that aggregates updates (posted questions, answers) from specified users? Not a friend list, but something like a 'wall' for followed individuals?
This would facilitate user interaction in the Q/A loop, which is hardly "social networking." In contrast with comments on the top answer to this question, I argue that it would only enhance StackOverflow's function as a question and answer forum.
We already have the ability to star a question, so why not a user?