It's revolutionized all sorts of areas - medicine, science, art, performance, research, entertainment, communication. Without it, it's feasible to say that even personal computers wouldn't be so prevalent. Information is the new lifeblood of a huge number of industries, and it's made the world that much smaller.
Event wise, it's a bit harder - I'll admit to not having paid too much attention to see if things I knew from home had also happened here, at least the same way. But wars are fought differently because of the internet, news is handled differently - It's truly phenomenal.
Even here - we're all from different places, different times, different worlds - and without the internet, and the ability to interact with others who have dealt with the same or at least know about it, we'd be so much more lost. I know a lot of people here have grown up with it, but it's still so novel sometimes, what can be done...