Why isn't this automatic? Maybe it's a privacy issue, but it seems to me that some sort of neural-networky thing (excuse my AI ignorance) could automatically group these. Especially with some training from the user, I bet a program could determine for 99% of cases what 'tab group' a tab should go in with broad enough categories (development, camera shopping, photo browsing, social networking, etc.).
The Tab Candy team has plans for "rules" that would work kind of like mail filters for placing new tabs into groups automatically. And these would be exposed to add-ons, if someone wants to write more complicated classification code.
