I've been really curious about how companies can leverage data to drive traffic. While APIs are a great tool for developers, the average consumer could never use them.
Naturally, when Yahoo! Pipes launched I was thrilled. It brings APIs a little closer to the consumer side.
While they still have a world of ways to go, if you're curious to see how the consumer tools side is evolving, I suggest checking out John Musser's presentation from the Web 2.0 Expo -- one of my favorites!