I am very interested in the smarter browser. I am still very excited about Chrome despite its somewhat slow launch. It may not be the killer app in this game but it's a step in the right direction.
One recent development in this area is Adaptive Blue's Glue browser extension. I don't think there's enough context in Glue yet. It reminded me of MyBlogRoll. Even now that it's quite liquid, it fails to delivered promised value to the user.
The context is critical. The second most natural company in the world to begin working on the browser is Facebook. (The first was Google.) I also think there's quite an opportunity for Grou.ps here. Because, a group itself provides plenty of context. The trick there is for the user to be able to separate his activities in multiple groups.
Another opportunity exists for regional markets. If you built a browser that abstracted and made sense of Yandex, Vcontacte.ru and Mail.ru, it would be quite relevant for Russians.
How about Turkey?
Keep watching the browser.