This, for me, is one of the most important features out of a modern browser. The short of it is that it allows you to very quickly sandbox the web and run multiple websites in differing states.
In FireFox, which I think is the best implementation of this, all; web session data, cookies, etc. are housed within a user curated container. You can have one for work, personal use, shopping, banking, etc. and choose whether to permanently assign website to 'always open' in the specified container or just a one of instance.
This is fantastic for managing Google and other service logins between work and personal, purely based on what container the browser was told to open the website in.
The key bullet points Mozilla use for the feature are a pretty good reflection on the use case:
- Sign in to two different accounts on the same site (for example, you could sign in to work email and home email in two different Container tabs.
- Keep different kinds of browsing far away from each other (for example, you might use one Container tab for managing your Checking Account and a different Container tab for searching for new songs by your favorite band)
- Avoid leaving social-network footprints all over the web (for example, you could use a Container tab for signing in to a social network, and use a different tab for visiting online news sites, keeping your social identity separate from tracking scripts on news sites)
I would love to see this implemented in a browser as performant as this one 👍️ although I could imagine it being a lot of work creating the required abstraction layer, probably more a wedge, between the current methods being used to cache and store web session data before even approaching the task of adding in the UI/UX side of things.