NetShow was Microsoft's original framework for Internet network broadcasting, intended to compete with RealNetworks RealMedia & Vivo (acquired in 1998 by RealNetworks). It was later renamed and marketed under the Windows Media umbrella.
NetShow 1.0 came out in 1996. A newer version, 2.0, was included in Windows NT 4.0 SP3 in 1997. Version 3.0 came out mid-1998. The whole product line was renamed Windows Media in October 1999, four months before Windows 2000 appeared.
The NetShow name is still carried on in the user-agent string in current versions of Windows Media Player, which reports as "NSPlayer".