Believe it or not, I didn’t know about Flash-blocking until recently. If you’re Firefoxy, you need FlashBlock. Safariers want clicktoflash. I’m one of the few, the proud, the Camino users; for us it’s just a tick-box in the standard preferences. (And what is this “IE” of which you speak?) It’s amazing, first of all, how many little gobs of Phlash Phlegm there are all over commercial pages, and second, how much lighter-weight the whole browsing experience is when you just Turn ’Em All Off.
I already thought Apple had it right about omitting Flash from the iPhone. Hey there Palm and Android and so on, if you do allow Flash to run on your handsets, at the same time you have to introduce a way to block it.