And if you follow the link at the bottom of that post, you'll find what the thermocline consists of:

>There was upper Apple management, basking in the sun; the great mass of Apple employees below; and between the two, a constantly shifting layer of middle managers whose function appeared to be to keep the two groups from mixing.[0]

[0] http://andstillipersist.com/2006/08/guerrilla-programming-li...