When you graduate, there's a possibility that LinkedIn may not still be considered a joke, for better or worse.

I'm 27 and killed my LinkedIn account because 1) I just don't find them to be a company that is concerned with user privacy and 2) I have not once seen a benefit to being on it.

I think it probably depends on your industry. I'm a programmer, so maybe if you're a finance major it's more useful.

wait until you get out of college, and start looking for a job, LinkedIn will have the last laugh.