Recently I gave up the life of a University web developer and moved to the exiting world of semantic web and library web services.
One of the nice things about the whole experience has been that Twitter has worked as a great bridge into the new role. It's that whole ambient intimacy thing. Before I'd even set foot in the organisation as an employee, I had connections with people within it. More importantly, in a way, I felt connected to it.
Once I'd announced my acceptance of the new job, I had a raft of employees and well-wishers from the company's sphere of interest, all making me feel that I was already part of the place before I'd arrived; Helping me with my transport queries, sharing useful knowledge, making me feel part of the culture and so on.
That's a powerful thing. Feeling you're welcome, appreciated and valued, before you're even in the office.
The point here is that the untapped use for Twitter is bridging transition into new employment. Given that the tech industry is fairly notorious in its inability to retain talent from offer to actual arrival, that feeling of belonging to culture, which twitter can create, is a powerful tool in the recruitment arsenal.
Of course, I only applied for the role due to a tweet by Rob Styles, who I originally followed as another web person in Birmingham. So it's a double edged sword, what helps you integrate new employees might also allow your talented employees to be lured away...