In tonight's update for Counter-Strike: Global Offensive, Valve included a new, unannounced feature that they're calling "Prime Account Matchmaking." It's in beta right now (obviously) and as of right now it's not yet active, but you can still sign up for when they do make it active. All you need to do is start up the game and look in the top left corner of the main menu. You will see a method to opt-in to this new system.

So, what exactly is Prime Account Matchmaking?
CS:GO is running an experiment to find out whether players will have a better matchmaking experience when they are matched with players who are using a phone-linked CS:GO account.

To join the experiment, you'll need to upgrade your CS:GO account to Prime status. Just click the UPGRADE button below, which will bind your Steam phone number to your CS:GO account (provided it qualifies, see the F.A.Q. below).

If you own multiple CS:GO accounts, be sure to upgrade your favorite one since you can only upgrade one CS:GO account to Prime status with your qualifying phone number.

Once there are enough Prime accounts, we will begin Prime Account Matchmaking and will start prioritizing matching Prime status players with each other.

There's nothing else you need to do (except convince your friends to click that Upgrade button too so we get enough players to start testing!)

It seems like this might be a way to combat things like cheaters (that have to purchase multiple accounts) and smurfs (additional accounts typically at a lower rank than a main account that are used to stomp players that should actually be in that ranking). It may also be used to force a more strict ban method in that if you get VAC banned on a Prime Account, your number is also banned. So not only would cheaters have to buy the game again, they'd also have to change their number if they wanted to play in Prime Account Matchmaking.

Naturally, there is nothing stopping these people from not signing up for Prime Account Matchmaking. However, this still benefits those that do sign up for it as they will have a reduced chance of having to deal with cheating in their game. It's really win-win for everyone except for cheaters and those who unfortunately do not have a mobile phone number tied to their account.

I'm sure we'll have a more definitive answer for all of this once Valve makes a public announcement about this new feature (whenever that may be). Until then, here are the other changes made in tonight's update.

Changelog for CS:GO for April 21, 2016
UIMAPSOPERATION WILDFIRESDKhttps://github.com/ValveSoftware/csgo-demoinfoCOMMUNITY SERVERS