What does it all mean? Well, if you've been in the practice phase, your rating will be reset to 0, and if you add new people to your team after this point, you'll be penalized by 150 points of rating. So if you had a rating of 300 and added a player to your roster, your rating would be adjusted to 150. Sense made? Good! It's not wholly clear whether a team with a rating of 0 would be moved to a rating of -150, but I sincerely doubt it -- and to be honest, it shouldn't be too hard to gain 150 rating points.
If a player leaves your team, you won't be penalized, to the misery of PvPing trolls everywhere.
This phase will run until May 22, at which point Ranked Ladder Phase 2 will begin and team roster changes will not be permitted, so get your teams sorted out as soon as you can. Registration is open until the end of May 22, so if you want to get involved in the Arena Pass, it's not too late to sign up.
If you want your Murkimus, then now's the time to get in the 50 3v3 games required to get him on your live realm characters. Any games you played prior to the Ranked Phase won't count toward earning him, so get involved!
Also, don't forget that if you are in the top 1,000 teams at the end of the Ranked Ladder Phase 2, you'll be getting a Vanquisher title on the live realm. By signing up for this Arena Pass, you're also getting access to an exclusive Level 90 Arena Pass Realm once you've upgraded your account to Mists of Pandaria.
To the victors, the spoils -- and also to the participants in more than 50 ranked games!