Bob Metcalfe's law states that the overall usefulness of a network is proportional to the square of the number of people connected to it (because each of the N users can make N-1 connections). I was thinking of this while listening to a radio programme this morning about the

A similar multiplying effect must occur with databases on the net. The more data a particular database contains, the more people will use and add to it. The marvellous Internet Movie Database was an early example.

Now, I wonder if this one will ever really get going....