I seriously don't agree with working for free for "exposure and experience". Didn't HN just have a couple of posts recently about the serious negatives of unpaid internships?
This is pretty tech-specific. In many other fields, unpaid internships are seen as a good deal, mostly because their are so few of them and so many applicants. A friend of mine who recently converted an (unpaid) internship to a job in DC worked really hard just to land the internship. At the same time, he was learning the job but in no way provided the same benefit to his employer as a tech intern does.
Sort of adding on to that, an unpaid opportunity doesn't have to be an unpaid internship. An unpaid opportunity could be a CS student in college working on the website for an on-campus club, for example, or a public relations student serving on the executive board as the PR chair of an on-campus organization.
I think when facing a choice of 'doing nothing' vs. working on an open source project or unpaid internship, a college student should choose the free exposure and experience. Sure, if you can get a paid internship or work in your field, do that. But if you haven't yet, free exposure and experience is a great way to do something positive.
Good point here and I'd have to agree with you. Sure, the unpaid route isn't ideal, but then again neither is an internship in general. The whole point of an internship is to gain experience/see if you're a fit for working at the company full-time. Now, in the tech world, I fully understand unpaid internships at brand new companies with absolutely no money. What I don't understand is unpaid internships at PayPal. That's where I draw the line. But yes, when it comes to either working for free or doing nothing, most (rational) students will choose to work for free.