We could reduce the posting frequency to once every twenty or thirty seconds. This would reduce the amount of bot responses. We could also tie this built in limitation with reputation and thus encouraging beginners to take time in developing their posts and punish spammers for pushing trash. Lets say that you have no limitations at 25 or above (other than the few second delay mentioned above), and those below have to wait extended periods of time and sit in timeout, with the timeout being longer the further below 25 you are. The max timeout would be a day or something like that.