LinkedIn. I usually respond to most of the requests I receive because I think it is the polite thing to do.
Having said this, I am still unsure how academics might benefit from using LinkedIn. This is not to say that I don't believe that academics CAN benefit from LinkedIn--I have just not found it to be useful. For example, the only time I ever log onto the site is when I am responding to someone's request.
What am I missing?
How do you use LinkedIn?