First, because most companies don’t like their customers, whom they usually call “consumers”, and don’t want them bumming around on their web properties, leaving comments or asking questions on their pixel-perfect websites [3].

Second, because most companies are boring and would have a hard time doing social media marketing as described by Wikipedia, i.e. in being interesting and getting their customers to spread the word about them.

Third, because of the hype cycle: they're told that it’s a new world, that things will never be the same again, that it’s land-grabbing time, and that you need to get in early and make a killing. The same nonsense we heard when the pundits were extolling the wonders of the New Economy, in case you forgot. Which you probably did [4].