microSD memory cards are very popular for expanding the memory of cell phones because of their incredibly minute size. In fact, microSD cards (the m in micro is supposed to be lower-case) are currently the smallest commercially available memory cards out there, measuring about the same size as a fingernail (15 x 11 x 1 mm), making it about a quarter of the size of a standard Secure Digital (SD) card.
Initially developed by SanDisk, microSD were designed to be used primarily for cell phones right from the start. When they first hit the market, they were known as T-Flash cards, later being renamed TransFlash cards before their current name -- microSD -- was adopted. The current name came about after the memory card format was integrated into the SD Card Association, joining the standard Secure Digital (SD) and miniSD formats.
As of yet, there are no (or very few) card readers on the market that will directly link a microSD memory card with your computer. As such, when you purchase a microSD card, it will come with an adapter that is the same size as a standard Secure Digital (SD) card. The microSD card fits in the SD card adapter, which in turn can go into any number of readily available card readers (some laptops come with built-in SD card readers, some desktops now replace the standard 1.44 floppy drive with a multi-card reader, etc.). Where the microSD card goes in a cell phone depends on the model: some have an easily accessible slot on the side of the mobile phone, others hide the card behind the battery cover or behind the battery.
When the microSD format first hit the market in 2005 (after ratification from the SD Card Association), it was available in relatively small capacities: 32MB, 64MB, and 128MB. Since then, we have seen the much larger cards emerge from a number of different manufacturers (not just SanDisk), including 256MB, 512MB, 1GB, and most recently, 2GB. This increase in storage has a direct relationship with the increasing popularity of musicphones. As more people use their cell phones as MP3 players, the demand increased for capacities that could rival the portable music players on the market, like the Apple iPod Nano. We continue to see larger and larger flash drives, portable hard drives, and other storage media, so it should be little surprise if we start seeing 4GB, 8GB, and 16GB microSD memory cards in due time.
