Original: Along with Windows 2000 from the NT family, Windows Me was the last version of Windows that lacked Windows Product Activation.
Simplified: Windows Me was based on MS-DOS (as were Windows 98 and Windows 95), and is meant for people using computers in their homes. Windows 2000 and Windows Me are similar in looks, but Windows Me has features that families find useful, while Windows 2000 was meant for businesses.