Microsoft's Windows Mobile extended its lead over other PDA platforms, as it accounted for 54.2 percent of PDA OS shipments. RIM OS accounted for 22.5 percent of the market, followed by Palm OS at 13.4 percent.

Gartner defines a PDA as a data-centric handheld computer weighing less than one pound that is primarily designed for use with both hands. These devices use an open market operating system supported by third-party applications that can be added into the device by end-users.

They offer instant on/off capability and synchronization of files with a PC. A PDA may offer WAN support for voice, but these are data-first, voice-second devices. Smartphones offer all the attributes of a PDA, except that smartphones are voice-centric, and are primarily designed for one-handed operation.