What does "beta" mean for an evolving web application?

Question

I used to understand "beta" as "feature-complete". Web applications rarely are ever feature-complete and rather evolve slowly with time. So does "beta" have any specific meaning with them or is it just a gimmick?

Answer 1

It's a pre-emptive disclaimer. "Go ahead, use it, but go easy on us if something collapses into itself and becomes a black hole."

Answer 2

In web 2.0 it does seem to mean nothing at all.