How does it work?

Match Making Beta Passes are now being distributed! All owners of the original Beta Passes are now generating Beta Invites, which can be sent to anyone on their friends list or anyone on the server they are playing on. Once sent, the recipient will have a new Beta Pass, which in turn will start to generate Invites. Beta Invites are being generated in waves (presumably to control the rate of distribution). The wave number is stored as an attribute on the Beta Pass and Beta Invite items. Each wave normally generates 1 Invite, but will occasionally generate 2 or more Invites.

Distribution Schedule

Passes seem to get distributed at specific times, this table shows when the first Invitation of each wave was generated. Furthermore, knowing that there were ~100 original beta passes we can calculate the theoretical maximum number of passes had all invites been sent prior to the subsequent distribution wave. Also, since Valve have occasionally revelaed the number of passes activated I have been able to add an adjusted 'likely to exist' number.