It is well known that IE security has been compromised too often and made public loud and clear. The trend of switching to Firefox seems to pick up whenever one of these holes gets uncovered.
Firefox also has some short comings but they do not seem to upset users nearly as much. Rebellion trend against the big guy (MS) is still cool way to think and act for some. Latest statistics give Firefox as much as 11% user base while IE is slowly losing its base. Slowest to switch are corporate users but that has started to change as well.
As long as there is competition we are all to benefit.
Dautovic 