1) Sure, I'll fix the bug myself, but does that help the other million users?
As much as Firefox’s popularity statistically has shown that it will become a larger target for hackers, its popularity is also what keeps it secure, ironically enough. Firefox is built upon what is called open-source software, meaning that anyone can contribute to Firefox at any time (with limitations in place to avoid abuse of the code). Because of this foundation, bugs are fixed very shortly after their announcement. Internet Explorer has a problem in this area because any bugs reported must be thoroughly tested by the Internet Explorer developers before they can be fixed, while if someone finds a bug in Firefox they can fix it themselves.