The document defines a personal digital assistant (PDA) as an electronic organizer originally designed as an electronic calendar, contact list, notepad and reminder with handwriting recognition. It describes how early models like the Apple Newton laid the groundwork, and how Palm popularized PDAs in the 1990s. Modern PDAs typically have a touchscreen, memory card, and wireless connectivity. They usually include calendar, contact, and note apps, and sometimes email and web browsing. The document highlights increased capabilities from Microsoft's Windows CE and Windows Mobile, as well as attributes of popular Pocket PC models.