out != beta testing
Beta testing is allowing an early version of the product out to a, normally restricted, group of willing victims (sorry: users) to get feedback to help fine tune the product. It also stirs up a bit more interest in the product before its finally released.
The advantage for the users is that they get to play with it before everyone else, often for free unless you are tied into a "pre-order" scheme. They also get to contribute to the finished product by expressing their opinions to the developers.
The disadvantage is that you are getting a warts-and-all early version of the product. It will probably be buggy as an ant-hill and have gameplay problems that make it less than fun a lot of the time. It will have lots of features planned for the final release completely missing until closer to (or at) release. It could put you off using the final product.
Some, but not all, developes do this. At what stage they do it also varies greatly from developer to developer: it could be just from just a few weeks before release up to years before final release.
There are also pubilc and private beta programs - private often means "by invite only" so you have to know someone who knows someone ...
Some products might have both - start with a private scheme and then widen it out.
Usually, whether private or pubilc, they will have a limited membership - you have to register interest by a certain date to get to take part.
