A great phrase coined by Glenn Reynolds: TCS: Tech Central Station - Horizontal Knowledge.
It's best understood by thinking about its opposite: Vertical Knowledge. The stuff you get from the boss or the MSM or the person at the front of the room.
Whenever I go to a conference, I learn more from the people in the lobby. And the web is one big big lobby.
There's a throwaway line in his post that I really enjoyed. Glenn riffs about the fact that there's no way, in 1993, that anyone could have predicted the Internet of 2003. In fact, critics might say that even if we planned for it, we never could have built it. Then he says:
Actually, that final statement is true. If we had started planning in 1993, we probably wouldn't have gotten here by now.
Planning implies vertical, top down thinking. And in many areas, it's backfiring.