Here on Stack Exchange you have to wait 15 minutes before posting another question.
But from a general standpoint, where quality isn't a must/enforced (something along the lines of a forum, but more Reddit style), how much time is considered acceptable before a user loses patience?
Making a user wait before posting anything has the added advantage of squeezing more queries per second to the db for one reason, another one being less intentional flooding/spamming of a website from a malicious user.
What could be acceptable? 30 seconds, 1 minute, 3 minutes, 5 minutes, 10...?
And in the case it's bad UX practice which one of the following proto-alerts would help in psychologically alleviating the waiting time for the user?
Replace 30 seconds with any amount you think is the right one.
I want you to think as if you was the targeted user in such a site.
Otherwise, what techniques do you think could be used other than the proto-alerts illustrated above?