If you like, you can uncheck the "Use the selected profile without asking at startup" checkbox to have the window show up every time you start Firefox (which is defined as loading Firefox when there's no Firefox window already open). Doing this has the additional side benefit that if an application tries to open Firefox and load a new URL when you don't have any Firefox windows open, you'll be alerted to it by the Choose User Profile box - very useful if your normal profile takes a long time to load!
If you want, you can add the "-no-remote" switch to tell a new Firefox process not to connect with any existing one, which will allow you to open a new profile in a different browser window while you've still got the original running in other windows. However, those windows will share the same taskbar grouping, so I'd recommend you apply a different theme to the new profile to allow you to distinguish the two.
(Note: You should not use "-no-remote" by default, as a browser profile can only be open by one process at a time and you won't be able to open new windows through your shortcut icon.)
Of course, none of this will defeat the multiple-browser fingerprinting techniques mentioned in the article, but it's still incredibly useful.
I'm not sure if there's an equivalent in Chrome, or at least one that goes as far as Firefox does.
Sounds a bit like local Docker for browsing?
Everyone would download the same Chrome container with the exact same clean config and software rendering so the canvas/WebGL fingerprinting yielded nothing?
No ...
That is, unless I can easily script the destruction and recreation of the guest account, and automated install and configuration of my chrome setup ...
The idea here is that I set up chrome just how I want it and deploy and redeploy that "container" over and over - destroying it and recreating it after each use. Possibly with multiple instances running simultaneously ...
For the fourth or fifth time this year, in response to a thread about browser privacy, I am reminded that what I really want is the ability to jail/chroot a browser.
Firing up a full-blown VM for a browser ("banking profile", "twitter profile", "sketchy online store profile") is way too heavyweight and resource intensive. I want a totally, totally clean slate (restored to post-install defaults) to restart certain browsing sessions with (and dispose of when I am done) but a full virtual machine is too expensive in time and resources.
But if I could jail a GUI application ... then there would be almost zero resource overhead and the jail would die quickly when you're done.
jailing a GUI application is not that well developed of a use-case. Further, OSX doesn't even have a jail command.
I wish this was an established use-case - I would really like a totally throwaway browser profile that I could reset and re-use.