You can read complete history and a lot more information on https://en.wikipedia.org/wiki/Mozilla_Firefox .
I personally have been using Firefox and Internet Explorer for years. Well, both of them have disadvantages and inconveniences, but in overall i’ve been more satisfied with Firefox.
First of all, Firefox is more stable compared to Internet Explorer. As I experienced more crashes and application errors on Internet Explorer, I had very few crashes on Firefox.
From security point of view, I always felt more secure while browsing with Firefox. On Internet Explorer you get a lot of add-ons which cause severe security issues and most of the time cause application crash.
Even spywares are more common on Internet Explorer.
Some people say that they are used to Internet Explorer and do not want to switch to a new browser! Let me assure you; you won’t find any difficulties when switching to Firefox, because:
– It is very easy to use.
– Imports your Bookmarks, Favorites, and more setting from Internet Explorer if you want, and it does it AUTOMATICALLY, with no headaches!
– It is Very stable.
– You can customize its look to what ever color and style you like. It’s not like IE which forces you to like it!
– You can install and remove the add-ons you like and need. No headaches!