I had a funny moment earlier this week when I showed Google's Chrome to one of my friends. She was floored that one of the top nine most visited sites featured on the browser's start page was Woot.com. Given how much browsing I do as part of this job I suppose it was surprising even to me, but it's also a hint of how intriguing your browsing history can be to others.
A service called Timelope is banking on that idea, letting users share their browsing history (or at least selected parts of it) with the rest of the world. Unlike Friendfeed which aggregates just the items you want from the sources you have chosen, Timelope posts all of your activity in one large stream and does it passively without requiring you to click on anything out of the ordinary. You can then befriend other Timelope users and see what they're looking at (almost in real time) as long as they're sharing.
All of this hinges around a browser plug-in that currently only works for Firefox. You simply plug in your user name and password and it pipes over the data in the background once the page has loaded. You can turn it on and off with a just a click, and it remembers its state between browsing sessions so you don't accidentally start sending off things you don't want others to see.
There are some obvious privacy concerns here. Making what you're viewing online public, able to be searched, and timestamped is a very open window into your habits and who you are. There are, however, some decent protection measures you can instate, like an anonymous log-in and both a black and white list for controlling which sites are shown to others, even when the plug-in is turned on.
Another company that offers a very similar service and a slightly deeper analysis of your habits, along with a way to create private groups is Hooeey, which back in late 2007. I thought then, as I do now, that these services can be incredibly useful for a certain few, but are likely to instill fear in people who are already worried enough about having their e-mail passwords stolen, let alone sharing what they're doing with strangers.
Timelope is currently in private alpha but was still accepting new sign-ups when I published this.