I like this: it goes to the core of the privacy/surveillance debate. And, as Fred Wilson says, it's not for everyone yet. However...
Imagine if you had a single data feed, fredsactivity.xml, that was hosted on the web and you could share with web services. I'd give it to Amazon to get better recommendations. I'd give it to Google Reader to find interesting blogs to read. I'd give it to Twitter to get better recommendations for people to follow. I'd give it to Netflix and Fandango to get better movie recommendations. I've give it to Goolge to get better search results.
I still believe this is going to happen. The burst of activity a few years ago may have stalled out, but I think that's a temporary pause, driven largely by the fact that the mainstream Internet user wasn't ready for this. Maybe they still aren't. But I am.
More here: Musings of a VC.