BlueTracker

Accurate. More info about Blizzard Betas in general here.

Though if you haven't gone and opted in for Diablo beta opportunities, I highly encourage everyone to do so. A lot of folks forget to do it at announce and opt in after Beta has started. While it's not really a first come, first serve situation, opting in after Beta started pretty much ensures you aren't getting in for the first wave (since we don't know you're interested).

So it's a good reminder.

Ah, you're right. The process has changed significantly since the last beta I worked on (which was Rise of the Necromancer).

This is, indeed, to sign up for the newsletter and any additional information we might release, including when beta sign-ups go live.