Spamming: You are forbidden from posting without a legitimate reason (in such a way that it does not contribute to the outcome of the topic or thread), off-topic posting, and repeating posts with an illegitimate objective. (From the acronym, S.P.A.M.: Stupid, pointless, and annoying messages.)
These are easily identifiable if you follow the acronym. If the message is "stupid" and "pointless," remove it. If the message is "annoying," for example, being restated and reiterated over and over again, remove it. It is also spam if it is off-topic and has nothing to do with the thread. However, knowing if the post is in the proper place requires you to read and analyze the thread.
Flaming: You are forbidden from speaking in a derogatory and insulting manner towards another member. This also includes flame-baiting in any sort of instigation. If you are found flaming the staff, the situation will be heavily regarded.
"Shut the **** up, you ugly piece of ****." Analyze the message and interpret it in every way. Is he/she joking? is it the point of the thread? what is the goal of the message? what is the context of the message? If it is an actual insult towards another member, remove it. You should also note that vulgar language ("shut the **** up") does not warrant an infraction. The actual offense ("you ugly piece of ****") makes it flame.
Pornography: You are forbidden from posting any image containing nudity on the forums.
Remove all pictures including nudity. This means they show genitilia and sexual procedures. If they are not being shown and being properly clothed or censored, do not remove it.