Well, I found several jobs using linkedin, so for me, it works. You have to be a bit harsh on accepting links with people you don't know, but I can't complain...

And there's the odd funny joke too -- once I got a job offer for building a supermarket on the south coast. You know, I'm a 'software architect' after all, got to know how to build supermarkets...

(well I did participate in projects that looked a lot like oil refineries, to be fair ;-))