overrunning a fixed-size buffer with excessively large input data. See also buffer overflow, overrun screw, smash the stack. 2. To cause a newsgroup to be flooded with irrelevant or inappropriate messages. You can spam a newsgroup with as little as one well- (or ill-) planned message (e.g. asking "What do you think of abortion?" on soc.women). This is often done with cross-posting (e.g. any message which is crossposted to alt.rush-limbaugh and alt.politics.homosexuality will almost inevitably spam both groups).