Try to keep your posts as constructive and as relevant to the topic as possible....as in, you can post funny one-liners, but only where they make sense
Example: if there's a topic about a new game trailer, and someone just posts "Nice!", "Not bad", "Not interested", or "Good thread", it can be considered as spam....or when someone goes completely off-topic, without having made a single on-topic remark throughout the thread
Hope that helps