I'm concerned about my privacy while browsing the web, and for my general browsing I have a special configuration similar to the one presented here: https://gist.github.com/atcuno/3425484ac5cce5298932 Basically I have a couple of add-ons that help to reduce tracking and advertising, a user-agent spoofer, and other builtin privacy settings (like clearing cookies on close). I am primarily concerned with making sure every web search, article I read, or visit to a web site with trackers is not connected to one persistent browser fingerprint or id that can be also connected with my real-life identity. Now, whether or not these efforts keep me safe from the persistent profile that can be tracked is a question for another time. ***What I want to know is if another "profile" in the Firefox profile manager for online logins associated with my real-life identity (bank, email, spotify, library, etc.) will somehow ooze into the "private" profile I created. *** The "login" profile won't have all of the privacy addons and settings as the "private" profile, because they too-easily break logins, and because the profile will already be associated with my real-life identity, so I don't plan on using it except to browse those sites. Cookies will be allowed to stay, and no more than basic adblocking. Previously I used Chromium for this purpose, but I don't want to. Firefox works better in many ways. It seems like I should be safe doing this, as each new profile appears to have a completely blank configuration and cookie jar, but better safe than sorry, right? THANK YOU for looking at my question and I hope you can help!