Wonderful idea! Possible improvements: having history divided by container, so it is possible to delete a container's history. Also possibility of deleting a specific container's cookies. Would be great if there were more "built-in" containers for popular sites, just like the Facebook container. It would be nice to implement the same link functionality as the Facebook container: when a link is clicked, if it goes to a website not in the container, it is open by default in the default container.