"Benefits ranging from in-game content unlocks, early access to beta tests and demos" are promised to Gun Club members, plus "exclusive access to development teams."
The first games offering Gun Club perks are Battlefield: Bad Company 2 and Medal of Honor. Those who own BC2 and pre-order MoH will get into its multiplayer beta slightly earlier plus "early access" to the M24 Sniper Rifle when the full game launches.
"This program takes our games from being individual launches to being part of an ecosystem within our portfolio, while showing fans our appreciation for their loyalty," explained EA senior VP of marketing in the announcement. "The Gun Club gives us a platform to cross-pollinate our games, dialogue directly with players and add value to the entertainment experience for fans."
Sounds like Ubisofts thing that I don't actually know anything about because I don't buy their games anymore.