MMC also stands for Microsoft Management Console.
A MultiMediaCard (MMC) is a tiny memory card that uses flash memory to make storage portable among various devices, such as car navigation systems, cellular phones, eBooks, PDAs, smartphones, and digital cameras, music players, and video camcorders, and personal computers. MMC was jointly developed by SanDisk and Siemens AG/Infineon Technologies AG, who introduced the product in 1997. About the size of a postage stamp, MMC weighs approximately two grams. This is similar to the Secure Digital (SD card), and smaller than older memory card formats, such as the SmartMedia card and CompactFlash (CF card). By October 2002, the MultiMediaCard offered a range of storage capacities up to 128 MB.
Like SD and CF cards, MultiMediaCards are much more rugged than traditional storage media. All three cards have an operating shock rating (basically, the height you can drop them from and still have them work) of 2,000 Gs, compared to a 100-200 G rating for the mechanical drive of the typical portable computing device. This translates to a drop to the floor from 10 feet, as compared to a single foot for the mechanical disk drive. Both MMC and SD cards use metal connector contacts, instead of the traditional pins-and-plugs, so they aren't as prone to damage during handling.
MMC, like SD, features encryption capabilities for protected content, to ensure secure distribution of copyrighted material, such as digital music, video, and eBooks. The MMC Association (MMCA), whose members include Hewlett-Packard, Hitachi, Nokia, Sanyo, Siemens, and Palm, is dedicated to the promotion of MMC as an open global standard.