The popular and aggressively named website SlashGeek recently did a feature on Opera where they looked at 5 of the top browser innovations by Opera that has been copied by others that we now take for granted:
Funny that they should mention popup blockers. When I started using my current browser, one of its most attractive features was the popup blocker override-- at a time when only the most cutting-edge browsers* even had a blocker.
Incidentally, I can't stand Speed Dial, and do everything in my power to stop browsers from showing it. Some are more amenable than others.
* That is to say, all browsers other than Guess Which One.