I use LinkedIn quite a bit. I've found that it serves a very effective purpose (something that can't always be said for more chatty social-networking sites like MySpace): recruiting. I've done all my Alfresco recruiting through LinkedIn, and have ended up with excellent employees and no recruiter fees. Zippo.
Now LinkedIn in opening up its platform to outside developers, in an effort to compete with Facebook. The timing couldn't be more opportune, as LinkedIn offers something that the other social-networking sites don't: a place for professionals to get work done, rather than throw poo at each others' "walls," as the New York Times reports:
The move is one of several LinkedIn is making, including launching a beta version of a redesigned home page, to keep its less flashy but more business-minded contacts network site vibrant alongside rivals MySpace and Facebook. LinkedIn said it wants to be a hub for business information.… Read more