Web browsing is no longer a one browser per person activity. And that's not just about a family sharing a single computer or tablet. Even a single user sometimes needs to use the web as different persons. And no, this isn't a case of schizophrenia. In order to support the not so unusual use case of a single person having different accounts, personas, and habits when browsing the web, the Firefox team is playing around with "Containers" that separate those virtual users, and their data, from each other.