Spamming--derived from a famous Monty Python sketch, is the flooding of
appropriate media with information (such as repeated very long 'say'
commands). Unintentional spamming, such as what happens when you walk away
from your computer screen for a few minutes, then return to find several
screenfuls of text waiting to scroll by, is just a source of irritation.
Intentional spamming, such as when you repeat very long 'say' commands many
times, or quote words at someone, is usually frowned on, and can get you in
trouble with the MUD administration.