That's basically what I use LinkedIn for. Well, that, and occasionally looking up where someone or other works. I know it's "supposed" to be good for a whole lot more but my use is pretty limited. And, yes, I get mail I don't care about from LinkedIn. I could probably turn a lot of it off but I'm pretty good at ignoring lots of routine emails I get from lots of places.
btw, am I the only one who get's confused by these "I quit xxx" thinking it's a post by a former employee?