In essence Firefox profile encapsulates user information: bookmarks, cookies, history, private information, e.g. passwords and so on. Which makes them very useful in many occasions, e.g.
- Different people sharing the same computer and not willing to create different users on operating system level. Especially with blooming social networks, blogs and other sites where logging in is required, it’s much easier to keep different profiles, than log-out and log-in each time, to each site.
- Even for the same person who is using the same machine for different purposes, this feature can allow to separate the roles of the machine, from web browsing perspective, e.g. “home”, “work”, etc.
- Sometimes creating separate profile is also good when working on a specific project which requires a large amount of bookmarks, which can be deleted once the project is complete.
- Finally profiles are very useful in testing, as they allow to simulate different users without the pain of creating different sessions on OS level
Without further configuration Firefox usese a default profile (in early versions of Firefox you could see it every time you opened a browser). In Firefox 2 or 3, however, you need to start Profile Manager purposely to see the profile you are using and to create/delete additional profiles.
Summary of the commands:
Profiles are defined in the file called profiles.ini, on Windows located in
%APPDATA%\Mozilla\Firefox folder. An explanation of the file structure and the meaning of the values is provided on Profiles.ini_file Mozillazine page.
I couldn’t find an official reference to confirm this number, but from what I’ve seen, Firefox allows up to 20 profiles per Windows user.