NICK PROPERTY: PMREPTRACK
Usage: PROP <nick> PMREPTRACK [<repetition limit>]
The PMREPTRACK property attempts to block too many repetitions of messages sent to you privately. If one or many users send you a message very often (or messages that all are very similar), then the server will stop sending them to you, once the number reaches the limit set in PMREPTRACK.
/uprop pmreptrack 3