Hanna Rosin, former Style writer for the Washington Post and a current contributing editor for The Atlantic, takes the pulse of yoga in America in her December 2006 article "Strike a Pose." According to Rosin, the good old days of hard-core yoga--like that practiced by Jivamukti teachers and practitioners--have been superceded by the more mainstream yoga like Power Yoga taught by Baron Baptiste, a pragmatic blend of gym workout and church pep talk.
The article is not available online, but you can read a related interview with Rosin on The Atlantic's site here.