[fit2rule]

I heard it in the late 80's/early 90's, referring to Unix-based developers who could write a kernel module, device driver, user space daemon, user app - in fact I think I remember it referring to OSI and POSIX at first (i.e. can develop anywhere on the POSIX/OSI stack). I think its risen to popularity in the Facebook-era, but it certainly existed as a phrase and a concept in the 80's/90's.

[marssaxman]

That makes sense; I had no contact with the posix world back then.