"The guy interaction on the show is pretty dead-on," says Brad Bressler, 24, from Los Angeles, a software engineer and fan of the show. Says Matt Dentler, 25, a film-festival coordinator from Austin, Texas: "You feel like these guys are gonna have a tight bond no matter what happens."

Notice the ages on those fans? "Entourage" is HBO's lowest-rated marquee series, drawing only 1.5 million viewers per episode—about half the audience of "Curb Your Enthusiasm." But it's the right 1.5 million: the young city dwellers who drive the pop-cultural chatter. "Entourage" may be last in ratings, but it's first in buzz. "It's absolutely doing what it should be doing," says HBO's Carolyn Strauss. "The numbers don't play into our thinking as much as the buzz." Which is why the network has already picked up "Entourage" for a third season.