StarCraft 2: Heart of the Swarm clan system details
Blizzard still hasn't figured out how to link all of our minds with the protoss Khala yet, but it is giving us more tools to link up with our friends across the StarCraft 2 community. The Heart of the Swarm expansion will be introducing clan support, with a test build going live in the next major beta patch.
When you create a clan, you'll input a name and a 2-4 character tag that will appear in front of the names of everyone in your clan automatically. Strangely, clans currently have a limit of only 50 players. Blizzard explains that "Clans are geared towards teams of players participating competitively in StarCraft II," and they're "working on support for Groups: players who want to associate casually, and in larger numbers."
So let your squad/brood/tribe-mates know. And if you see tag [PCG] on the beta ladders, brace yourself for some pain.*
*Assuming Gold League or below. If you're Plat or better, you'll probably pass out from laughter and still somehow win the match.