Most is probably being used for savings as the potential for it to increase in value over years is ridiculously high. If bitcoin succeeds in taking over fractions of global markets, which is is poised to certainly do because of its efficiencies, then the market cap will be hundreds of billions, and valued above several thousand dollars each.

But, bitcoins are being used in commerce too. New merchants added every day. I know of at least 6 brick and mortar businesses in Las Vegas alone that have sprung up recently.

The success of bitcoin in taking over fractions of global markets also depends on its learning curve, both in how to use them and how to keep your bitcoins safe(while still having access to them everywhere you need). Right now that's a pretty steep learning curve for non-technical folks.

More and more places are beginning to accept Bitcoins. I frequent r/bitcoin on Reddit and there are posts, daily, about businesses that are starting to accept Bitcoin. Many online VPN services are accepting bitcoin to add another factor of anononimity. bitcoinstore.com is growing as well, they sell a wide variety of electronics.

Does anyone know if there's a good way to determine the fraction of bitcoin transaction that are food good and services rather than just other money?

It's called "bitcoin days destroyed", look it up.

That's really interesting, thank you. Sounds like a pretty imperfect metric, but I like its well-defined-ness.

Stack-exchange for others who want more info: http://bitcoin.stackexchange.com/questions/845/what-are-bitc...