“Austin City Limits” used to be the name of a nice, genteel little television program presenting live music to a Texas-based studio audience. But these days, ACL is an institution, and a wildly successful festival that is rapidly outgrowing its capacity. “ACL got huge in just three years, and the growing pains are obvious. Last Saturday, when the attendance passed 75,000, ACL felt like rush hour in a subway station with people walking in all directions, cellphones pressed to their ears, oblivious to the music… Monstrous crowds may generate excitement and boost the local economy, but they can just as easily turn a festival into one big drag.”