Prior to the rise of "Internet culture", one of the more interesting cultural barometers were the use of slang terms and other idioms. How many kids that grew up on the seventies still use the term "cool" to describe things. How many remember using the term "bad" to refer to something that they actually meant as "good". Most of us could probably think of hundreds or thousands of things we used to say - and that sometimes slip out in current conversation and horribly date us by their use - that we've allowed to fall by the wayside.
Internet memes seem to be another type of cultural barometer. They have a quick onset, and then a long period of "dude, that's so over" use-period ("FAIL", anyone?). But still, it makes me wonder how long these "over" things will persist. Will my friends' children understand "FAIL"? Will people that used these terms or otherwise participated in these memes still recall them decades from now. For instance, I sort of wonder what the reaction of people twenty years from now would be were I to walk up to them and say "badger badger badger"?