Macromedia Shockwave Multiuser Server (SMUS) is a server application specifically designed for use with the Multiuser Xtra in Shockwave sites and applications. It forms the backbone of some prominent online Shockwave games.
Supports Macromedia's Multiuser Server (MUS) Protocol over TCP and UDP (This is a proprietary protocol developed by Macromedia for use in programs and web applications generated by Macromedia Director)
Supports the seamless transfer of Lingo objects
Supports server-side scripting in Lingo
After version 3, Macromedia discontinued support of the software in favor of the Flash Communication Server, which does not support any of the above features.