Value in, value out. It isn't just "free", it's the return one gets for giving data so freely. We give Facebook information that ten years ago we didn't give any brands without getting something in return. We tell FourSquare where we are, have locations tagged on images, all under the guise of the stuff working better, but the return is less privacy.

Free tools are free because what we give away to them. And if the free tool claims ownership of your stuff (see Twitpic), then consider a paid service that has a business model that doesn't involve selling data.

So free also has a caveat: the cost is data. Give it, get the service for free.