As redrumola pointed out on another forum, OpenAmiga used to be for Amiga OS and also Amiga related OSes such as MOS, AROS, and OS4.
But somebody (Björn Hagström aka Orgin) poached the domain when it expired and made it OS4 only, thus excluding the developers. Now they are begging them to come back. Sad.
It was first conceived of back in 2003 by myself, Bloodline, Terminills, filson, alx and a couple of others, before OS4 even existed.
Terminills let the domain expire after we gave up due to constant abuse from "Red trolls" and then one of them nabbed the domain for OS4 specific use.
http://openamiga.net is the new domain and this time we have the support and blessing of one of the founders of Hyperion; Mr Evert Carton.