Mozilla’s Firefox browser is getting a new experimental feature today that aims to help you segregate your online identities and allow you to sign in into multiple mail or social media accounts side-by-side without having to use multiple browsers.

This new “container tab” feature, which is now available in the unstable Nightly Firefox release channel, provides you with four default identities (personal, work, shopping and banking) with their own stores for cookies, IndexedDB data store, local storage and caches. In practice, this means you can surf Amazon without ads for products you may have looked at following you around the web when you switch over to your work persona.

As the Firefox team notes, the idea behind this feature isn’t new, but nobody has figured out how to best present this new tool to users.

“How will users know what context they are operating in?,” the team asks. “What if the user makes a mistake and uses the wrong context; can the user recover? Can the browser assist by automatically assigning websites to Containers so that users don’t have to manage their identities by themselves? What heuristics would the browser use for such assignments?”

Mozilla acknowledges that it doesn’t have the answers to this, but hopes that adding this feature to the Nightly releases will allow it to do more research and gather feedback.

In its current implementation, Firefox lets you switch between the different personas and the highlights which one you are using in both the URL form and by presenting tabs in the respective colors of the persona that is using them.

The different identities still share the same browsing history, bookmarks, saved password, search and form data, but as far as the sites you visit are concerned, there is no easy way to tie together simultaneous visits from different browser personas, even if they are coming from the same machine. “This is because the site doesn’t have access to the user’s locally stored History,” Mozilla notes. “We only segregate data that a site has access to, not data that the user has access to. The Containers feature was designed for a single user who has the need to portray themselves to the web in different ways depending on the context in which they are operating.”

Mozilla notes that ad trackers could still fingerprint your browser (that is, use your IP address and the individual attributes of your browser and operating system to identify your device as you move between sites), even if you use different personas. “Containers are meant to help you separate your identities and reduce naive tracking by things like cookies,” the team says and acknowledges that this feature can’t replace Tor Browser or similar tools.

For the time being, this feature remains somewhat hidden and it’s too easy to forget what persona you are currently using and then unwittingly click on a bookmark related to another. It’d probably be good if you could also set different bookmarks for the different personas. That way, you’re less tempted to click on a news site when you are done with your banking or shopping session, for example.

Still, simply being able to log into two Twitter accounts at the same time or being able to shop without ads then following you around for years without having to use an incognito browsing session is worth the price of admission. Firefox’s current implementation of profiles, after all, is somewhat clumsy and most users probably don’t even know this feature exists.