The primary difference is what you saw was standalone software, where all this is done server-side. Couple that with the social networking, and suddenly you've got something that is taking off. People see these videos and are like, "Sweet, I can make these and I don't even have to have any special software on my PC, or deal with system requirements or anything.
Whatever you saw 10 years ago, almost nobody else saw. Not so with this. It markets itself.