These $ <= 0 sorts of internships seem concentrated in fields where social capital is highly valued -- politics, PR, talent management, etc. Could it be that young people from upper class backgrounds are the most likely to possess the social skills and pre-filled Rolodexes required to be successful in these industries? Even if this is not true, it is certainly possible that the head of a PR firm from a wealthy family could not imagine it otherwise. I also wonder if, in addition to no pay, the price of the internship is actually negative because of the reciprocity expected from the social connections used to secure the internship for the recent college graduate.

I am imagining a voice mail like this:

"Hey, Joe [the VP at the PR firm which represents Large Company X], this is Bob, [the internal head of PR from Company X] calling. Would you mind doing me a favor and taking a pass at my niece's resume? She's interested in PR and would love the opportunity to do an internship with you guys this Summer. The pay isn't as important as the experience, and she can stay in her aunt's apartment on the Upper East Side. It's great that we do business together. Talk to you later."

How much has Joe "paid" for his niece's internship?