Purpose of the Careers Service?

I've been giving some thought lately to the purpose of careers services. I'm not claiming this is exhaustive or can't be improved on, and clearly it's an over-simplification, but here's a first stab. Fundamentally I think it's about generating a 'push' from students and a 'pull' from employers. I'm really interested in comments from students, employers and other careers service professionals (or anyone else for that matter).