Who owns the trail of digital breadcrumbs you're leaving behind?
Is understanding who you know and how you know them and where you visit and what you're interested in and what you buy worth anything?
Perhaps you should own it. Richard Thaler's provocative idea shouldn't be that provocative, and it represents a significant business opportunity. He argues that you (not some company) ought to own your caller history, your credit card history, etc. If it was available to you as a machine-readable file, you could easily submit it to another company and see if there was a better deal available. You could make your preferences and your history (you, basically) portable, and others could bid for a chance to do better for you.
This is an idea that feels inevitable to me, and I think that entrepreneurs shouldn't wait for the government to require it. There are already services that scrape financial pages (like Mint), but it could go further. We need software on our phones that can remember where we go and what we do, software for our browsers that can create profiles that save us time and money, and most of all, software for our email that gets ever smarter about who we are and who we're connecting to.
Data about data is more important than ever, and being on the side of the person creating that data is a smart place to be.