For the record many companies never let an Alpha see the light of day (in large part because there are always people who think anything with an icon is ready for prime time and squeak accordingly). HTC is a tight group, and to their credit they would rather fix the problems (and spelling errors; it IS Dale after all) than find them so they're letting us help out, which is pretty cool.
Alpha: I have code, it compiles, now I have to find out if it actually works correctly. There are always issues; it's a work in progress, and new features are being added as the project progresses. Something that functions today might not function tomorrow because we're still writing the application, but without people to take it out and use it we can't find all the problems. This is what Microsoft releases to the general public.
Beta: We have a functioning product, but only a small group of people have used it on a finite set of machines. This is what you release to the world at large to get as many sets of eyes possible using it on many different platforms so the small nagging issues can be identified before a "production" release is issued. At this point new features are generally not added, but the existing features may be modified, fixed, and occasionally disabled/removed as necessary. Given no two systems are identical it's critical to get this to a wide audience. The is what Microsoft calls "SP1/SP2"
Production: We think this is ready for prime time; to the best of our knowledge all of the features work as intended, and general users should be able to make it work. If something gets to this point at Microsoft they retire it.
