I've been thinking about this one for a while. There are social libertarians; there are economic libertarians; the idea is less government. And at the end of the day, I think that this might be the best way of all to measure whether or not someone really is a libertarian:
What is out there, that you think is wrong, but nevertheless believe should be legal?
For example, as I mentioned the other day, I think prostitution should be legal - carefully regulated in the public interest, but legal; however, I do think there's something terribly wrong with selling sex services. I'm even bothered by the overly mercantile nature of much dating, by mothers who tell their daughters they should judge a man by the price on the ring he brings them, by the high class escort services that carefully step around prostitution laws, by gold diggers, and by "Who wants to marry a millionaire?"
I am at least a little bit of a libertarian in that way. I want the government to step in because there is a compelling public interest - not because my personal sense of right and wrong is affronted.