This idea seems to pop up over and over and over again, but I don't think it will ever really take off until it's built into one or more major browsers. _why's

This idea seems to pop up over and over and over again, but I don't think it will ever really take off until it's built into one or more major browsers. _why's Hoodwink.d was pretty fun though. Since you had to discover it first and then do a little bit of basic hacking to get in, it was a pretty neat little community.