If I want to learn russian or chinese it might not be worth my time to pay for classes, let alone a private tutor in the real world. Yet there's probably someone on the internet willing to teach for an hour for a tiny amount, below minimum wage. And perhaps there are some well-off families in Asia wanting to pay a native english person for tuition.

So in my idea I upload bitcoins to a website on which I could find various people willing to teach different things, at different times, at different prices, to suit me. I could also teach someone else and either withdraw the bitcoins or use them purchase lectures in new subjects. There would be a feedback/review system, so someone who wants to start can do so by simply teaching for free, then slowing increasing his/her price through fractions of a dollar, until whatever the market standard is. People particular good at teaching or who have very specialist knowledge could charge a premium.

The teaching would be done via voice communication and a Khanacademy style flash interface (graphics tablet recommended). Every session will be recorded. This could be used for security reasons (from speaking to strangers on the internet) and as a way to build a reputation by releasing past sessions.

Unlike a traditional website which does this (if they exist), you wouldn't have to hire tutors and pay in advance, or pay them minimum wage, or background checks. The peoples teaching would be people you've never heard of. All you do is create a website and take a percentage of transfers. People on the site would not need to donate large amounts of money or give their personal details in order to start, they could try it out by depositing just a few cents anonymously. They do not need to give away their identity beyond a username and a microphone output. The site would be very simple and entirely driven (wages, content, prices, reputation) by the users.