Mozilla Firefox?

What is Mozilla Firefox, & should I have it on my computer. There are free downloads on the net just wondering which one to choose?
Thanks for any help.

Mozilla Firefox is a browser like Internet Explorer and is considered safer one of the reasons is that it does not use ActiveX technology which is a security risk.

Well it's not essential and the above is actually wrong if your an apple fan safari is the fastest. I would suggest sticking with Internet Explorer for now.

I just find it brighter and better than the others. The computer geek who set up my equipment said, "Mozilla is just better.".
The guys in Manila at the Dell call center said they were relieved I had Mozilla as my browser cause it's easier. My local library has Mozilla as well. But, for some unknown reason, I can't use Paypal through Mozilla, I have to switch to IE.
Hope this helps. Try it and see if you like it.