Just One Thing

I've been wondering about the use of the word "beta" cropping up online. Yahoo Maps encourages use of their "beta" map service. Blogger, the site that hosts this here blog, is now "beta." Back in the day, Beta meant Betamax, the precursor to VHS. In animals, beta describes the middle ranks, as opposed to the alphas. What can it mean online? I haven't a clue but I am clearly going to have to spend hours looking it up because I have nothing better to do.