Winamp is a media player for Microsoft Windows originally developed by Justin Frankel and Dmitry Boldyrev by their company Nullsoft, which they later sold to AOL in 1999 for $80 million. It was then acquired by Radionomy in 2014.
WACUP (WinAmp Community Update Project):
WACUP (which can be pronounced as wakeup or wac-up or however you prefer it in your native tongue) is designed to work only with the patched Winamp 5.666 release to provide bug fixes, updates of existing features and most importantly new features with the goal to eventually become it's own highly Winamp compatible media player.
WACUP makes use of the benefits of Winamp being heavily based on a plug-in system so new plug-ins can add additional features as well as allowing replacements to be created which provide better implementations over the plug-ins natively included with Winamp.