I heard of it when the president of my university film-making society, a friend of mine, told me about it when we were scouting locations for a film shoot last academic year. He reckoned it was going to be the next big thing to hit the internet and was going on about all the cool new features, when I got home I saw the trailer on Youtube and it looked pretty amazing. He also said he might try getting all the other society members on it this year so we can have huge linked chat and do presentations and society-related stuff from home, at the moment all that's done on Facebook and isn't much good.
Since then (about six months, give or take), I've heard almost nothing about Google Wave. Maybe it isn't quite as revolutionary as people thought it would be...