From my perspective, the encounter is not overwhelming. I drive by and see one guy on a scooter, waving.
From his perspective, it initially appears that the encounters would be overwhelming - look at all of those people, and all of that traffic! - but in reality it isn't. The interface between the man and the passers-by is very simple. He sees people waving, or not waving.
Not like other things that I've seen.
P.S. For more discussion of Google Wave, see this post from TechChuff. Sample line: "Google Wave doesn’t actually *do* anything."