with the release of Winamp 2 and invited Winamp users to publish skins on Winamp.com. As of 2000 there were nearly 3,000 Winamp skins available. The ability to use skins contributed to Winamp's popularity early in MP3 development. With the increasing number of available skins, genres or categories of skins developed, such as "Stereo", "Anime", and "Ugly". Online communities of skin designers such as 1001Skins.com and Skinz.org have contributed thousands of designs; also at GnomeArt. Designers see skins as an opportunity to be creative: nontraditional examples have included Klingon, iPod, and Etch-a-sketch designs. The Winamp skin format is the most popular, the most commonly adopted by other media player software, and is usable across platforms. One example is the XMMS player for Linux and Unix systems, which can use unmodified Winamp 2 skin files. Winamp 5 supports two types of skins – "classic" skins designed to Winamp 2 specifications (static collections of bitmap images), and more flexible, freeform "modern" skins per the Winamp3 specification. Modern skins support true alpha channel transparency, scripting control, a docked toolbar, and other innovations to the user interface. History Initial releases Winamp was first released in 1997, when Justin Frankel and Dmitry Boldyrev, formerly students at the University of Utah, integrated their Windows user interface with the Advanced Multimedia Products ("AMP") MP3 file playback engine. The name Winamp (originally spelled WinAMP) was a portmanteau of "Windows" and "AMP". The minimalist WinAMP 0.20a was released as freeware on April 21, 1997. Its windowless, menu bar-only interface showed only play (open), stop, pause, and unpause functions. A file specified on the command line or dropped onto its icon would be played. MP3 decoding was performed by the AMP decoding engine developed by Advanced Multimedia Products co-founder Tomislav Uzelac, which was free for non-commercial use. It was compatible with Windows 95 and Windows NT 4.0. Winamp was the second real-time MP3 player for Windows, the first being WinPlay3. WinAMP 0.92 was released as a freeware in May 1997. Within the standard Windows frame and menu bar, it had the beginnings of the "classic" Winamp GUI: dark gray rectangle with silver 3D-effect transport buttons, a red/green volume slider, time displayed in a green LED font, with track name, MP3 bitrate, and "mixrate" in green. Overlength title appear as slowly scrolling text (or "marquee").. The skeuomorphic design somewhat resembles shelf stereos. There was no position bar, and a blank space