#1 Mozilla’s logo was a red t-rex – http://en.wikipedia.org/wiki/Mozilla_(mascot)
#2 The image depicts why the T-Rex would not be able to connect to the internet: its arms are so short that its head would smash into the ground before it would be able to reach low enough to grab the icon.
#3 The dinosaur was there because, without internet, we may as well be in prehistoric times
#4 They stole the idea from this shirt – T-Rex Running T-Shirt