a) It has a tendency to crash and lock.
b) The javascript console is pathetic (which sucks for development).
c) No cookie control.
d) No tabs.
e) It has a tendency to crash and lock.
f) No popup control.
g) Non-compliant with standards.
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42) IT ONLY RUNS ON WINDOWS (well, Mac too, but they're countering with Safari). (and it has a tendency to crash and lock)
1) fullscreen: meh. I run at high res. I don't need any more screen real estate.
2) nice: meh. Personal opinion only. Mozilla looks quite nice to me.
3) Very few websites that I want to visit don't run in Mozilla. Actually, I can't think of any. I use the microsoft.com knowledgebase from Mozilla as well. I run Flash, Java, .mov files, you name it, in Mozilla (and on Linux). And as you can see from the image issue being raised here, not everything runs in IE either.
4) see 1
5) see 1
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n) Who cares? More politics on your part. I use Mozilla because it works the way I want it to work.