There are a few different shoutbox message flood errors, I
think they are as follows: (WDZ will probably correct me if I am wrong
)
1. Too many messages by one person in a row (not necessarily next to each other though, something like 5 out of the last 7?)
2. Too many messages by one person within a set time period (5 minutes?)
3. Too many messages by all users within set time period (relatively new error, added when we tried to get to 10,000 shouts in one day by spamming)