Charging for online content is an old idea that's gotten new legs with such pugilistic advocates as Rupert Murdoch on its side. The News Corp. chairman said last week that was erecting a paywall around his properties, even preventing Google from surfacing content in search results. Now Peter Kafka of All Things Digital looks at several conflicting surveys estimating the number of U.S. consumers who currently purchase online content. The ambiguity of the numbers raises the question, "Who's Going to Pay for Online Content?" As he elaborates:

The new conventional wisdom is that sooner or later, consumers are going to have to start paying for some of the stuff they’re currently getting for free on the Web.

But will they actually pay up?

My gut says that people love consuming news, but only in the broadest sense –  Obama doesn’t really Twitter! What was Belichick thinking? — and that sort of stuff, which appeals to a very large audience, will always be free, and you’ll get it from Google (GOOG) or something like Yahoo (YHOO). Which leaves you with a small audience willing to pay for everything else.