Scott Duncan
In software development:
ALPHA TEST = Proof of concept. It works just enough to get the general idea across to other developers. IT'S NOT MEANT TO BE "PUBLIC". Many projects who have talented developers, tend to allow public testing, but this tends to be more "showing off" than proving a concept.
BETA TEST = PUBLIC TRIALS. In the lab it's very easy to reproduce results, but that tends to limit the real-world shit that can go wrong. When everyone is finished their contributions, and all their testing is complete, the developers release a TEST to the public. Google Mail was in "beta" for TEN YEARS. The general public is a GREAT resource for finding bugs. It's also good marketing for you services, if you can fix problems in beta test products. This is what the Ethereum team is doing. They will fall flat on their faces, or they will become stupidly wealthy... all because of this beta test.