I beleive it stood for Penguin AOL. A Linux AOL client. Previously located at pengaol.org. Obviously our trusty freedom protecting laws here in the united states fended off this great beast by allowing AOL to cease and desist pengaol.org, because obviously they were trying to profit from the popularity of the "AOL" trademark. The code is still in circulation somewhere like http://www.peng.apinc.org/.