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People who have multiple profiles or users on their Chrome devices can now take advantage of the new experimental multiprofiles feature. This mode gives you the ability to run Chrome OS with multiples profiles at the same time.

Once you've enabled the chrome://flags/#enable-multi-profiles flag in Dev Channel, you can start to run multiple profiles in your signed-in session by clicking on your profile picture in the system tray popup, selecting "Sign in another account", and choosing from the list of profiles you had previously added on your device.

Switching profiles is as easy as clicking on the profile picture in the system tray popup. Although I have to say that my favorite way is to use the handy <Ctrl> + <Alt> + <Period> and <Ctrl> + <Alt> + <Comma> keyboard shortcuts.
One nice thing, but still highly experimental, is that you can move windows to different profiles with a simple right click in the window top bar. As you can see in the video below, even the Files App even supports this feature.

And if like me you happen to stumble upon a bug, report it to the chromium team at https://code.google.com/p/chromium/issues/entry?labels=CrosProfile

Source: https://codereview.chromium.org/146193005