Blizzard has a history of employees/staff being given a limited amount of access keys which they can give away to friends and family. These have normally been very restrictive (just a few invites and all participants must agree to a non-disclosure agreement); allow an early preview to almost fully functional pre-closed beta code.
With Reaper of Souls though, the company has a made a break from this old system; where they also randomly invited 3,000 “active” people from the community. As the above article stated, there is no NDA involved, so part of the rationale is to use this opportunity as a marketing tool (which is why many streamers were invited).
Blizzard MVP’s were also naturally invited as were others from within the official forums, outside communities like Reddit, sites that cover the entire range of Blizzard IP’s, Diablo fan sites (diablo.incgamers and diablofans). Thus even though this initial wave is relatively small, it still represents the ability to gather a large amount of feedback, data, and statistics that will help with finding issues that normally wouldn’t be discovered until code hits a larger and more diverse testing pool (as in closed beta).
Some folks who aren’t familiar with beta testing cycles (not all companies use the same approach and systems though) may wonder why the limited number of participants.
The answer is simple: it’s not a full blown closed beta (with the backend infrastructure to support a larger number of testers). Blizzard’s F&F’s are normally small because its not meant to handle the concurrency loads like a normal test seed is). Closed beta (which is actually coming up rather quickly) while limited, offers even more of the player base a chance to play test the game (part of that random selection is based on ones system profile since one objective of the closed beta is to have the game tested on a wide variety of supported configurations across both Windows and Mac platforms).
RoS closed beta will be different from the Diablo III closed beta which was actually a beta test of the Starter Edition of the game (a very limited one in terms of the content that was allowed to be put to a more meaningful stress test). With the exception of boss fights, the closed beta will be the whole game (and they are going to be looking for a lot of constructive feedback before it goes golden master/release).
