flap, flap, gasp, gasp, flap, flop ...... that's me ... a fish out of water.
The following refers to spammers, only.
1) (guess) spammers post multiple messages, quickly
2) (guess) iHub time-stamps messages
3) determine a "normal" interval between messages posted by legitimate posters.
4) set a threshold at a shorter interval than "normal" as a flag.
5) trap flagged messages (messages posted in quick succession) and send them to purgatory.
6) this is unlikely to injure legitimate posters.
7) It may be necessary consider a message-length factor (Churak can post 5 messages in 3 seconds ... but they're all 25 characters, or less, including the obligatory derogatory character assassination.)
Fred