nagware

Nagware (also known as begware or annoyware) is a type of shareware that reminds (or nags) the user to register it by paying a fee. It usually does this by popping up a message when the user starts the program, or intermittently while the user is using the application. These messages can appear as windows obscuring part of the screen or message boxes that can quickly be closed. Some nagware keeps the message up for a certain time period, forcing the user to wait to continue to use the program.
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/nag'weir/ [Usenet] The variety of shareware that displays a large screen at the beginning or end reminding you to register, typically requiring some sort of keystroke to continue so that you can't use the software in batch mode. Compare crippleware.
[Jargon File]