In case they mean it for the web browser, it can be done in a safer way. Firefox supports having multiple browser profiles, which means different settings, addons, history, everything.

One way to create profiles and to open them is through the about:profiles page.

An other is to create separate desktop icons for these profiles, where the profile selection happens in parameters, and you refer to them by their name. The desktop icon would look like this: "....../firefox.exe" -no-remote -P "insert profile name here".
You can also have a desktop icon that just opens a small profile manager window, where you can select one from the list: "......./firefox.exe -no-remote -P", but be aware that unless you untick the box, this one automatically changes the default profile to the one you started with it.
The -no-remote is so that you can run them at the same time as other profiles, like your main one. You shouldn't have this for your main firefox profile. Details, because it has some consequences (nothing major, though).

Both ways should work on windows and linux.

If you need help with the desktop icons, let me know!

That's the one. I mostly use it to keep websites that I'm managing separate from everything else, so I use the software I mentioned earlier.

I've got a profile for myself too, and that has a few browsers, some small games, an antivirus, and my email client. I back it up to a portable drive, so that it's an extra backup, and can be taken with me if I know I'm going to be away from my computer for a while.