Last year, Jonas Lund made a website that broadcast his every online move. The project was called I'm Here and There, and it displayed Lund's browsing habits as links. Now, he's released a Chrome extension that actually takes over your browser, and replaces it with his.
It's called Selfsurfing, and I guess it qualifies as performance art? Can browsing be called performing? Whatever it is, I don't think I'd submit myself to it. No: I definitely wouldn't. My browsing is mine — it's like a window into my brain.
Rhyzome's got an interview with Lund, who details how the plugin actually works. When he visits Facebook, for example, you'll see your page instead of his — it mirrors URLs, not login sessions. Everything else though? Wide open. You can download the plugin here.