MMC

MultiMediaCard is a flash memory card format introduced in the late 1990s. It is the precursor of the much more popular SD card. It is not used often today.

Memory Stick Micro

Memory Stick Micro, commonly referred to as M2, is a small fingernail sized memory card format that is part of Sony's Memory Stick family. The cards measure about 15mm x 13mm in size, which is about the same as the competing microSD card format. M2 cards can be used in slots meant for larger format Memory Stick cards through the use of an adapter. The format can support capacities of up to 32GB in size.

MMS

The MMS specification allows for the creation of messages sent from one mobile phone to another that can contain text, pictures, audio, and video that can be optionally organized into slides in a presentation. Unlike SMS and EMS, the MMS system relies on 2.5G, or newer, data connectivity technologies such as GPRS and 1xRTT. As such, the configuration required for its use is often far more complicated than that of SMS. CDMA based networks and devices, such as those offered by Verizon Wireless and Sprint in the USA, generally do not support the full gamut of MMS functionality, and often offer what is simply called Picture Messaging. Such services typically function similar to email in that pictures and videos are merely attached to a text based message instead of integrated into a full presentation.

Memory Stick Duo

Memory Stick Duo is a small flash memory card format developed by Sony and based on the original Memory Stick format. An updated version, Pro Duo, was later released that allowed for larger capacities and faster transfer rates than the original. Duo and Pro Duo cards measure 31mm x 20mm in size.