The momentum of Facebook

There is a phenomenon called 'critical mass' which was originally coined for nuclear weapons and is defined as:

n.

1. The smallest mass of a fissionable material that will sustain a nuclear chain reaction at a constant level.

The current fascination with Facebook in the news and its popularity (with everyone I know) seems that it is reaching its critical mass... where its user base growth begins continually multiplying exponentially until there is no one else interested in joining, or another 'flash in the pan' fad takes over.
FB seems like it is always in the news lately and that is one of the signs of its surging popularity.