SpamThrottleClassic

Only allows a particular message to be displayed once, rather than repeated.
This happens under several different circumstances –
someone may be advertising for people to join a raid,
or advertising their wares in Trade chat, etc.
It can become annoying if they spam the same message over and over,
so this addon only displays unique messages – repeated messages are either
colored dark gray to indicate they are repeated, or can be removed entirely.
A timeout (call the gapping value) controls how often the exact same message
may be repeated, and this value is settable by the user.