My definition of spamming is posting posts that do not make sense or are not relevant to the thread they are posted in. Getting off-topic is not neccessarily spamming. If a post is off-topic then it is not spam if the thread has gradually changed topic and it is spam if the post jumps from one topic to a topic that is completely unrelated from all of the other posts in the thread that don't qualify as spam. A thread that makes sense and has some context is not spam. That's just my opinion.

I don't think spam is always bad. Spam threads can be fun. Spam that takes away from the quality of other threads is bad. Too many spam threads are annoying and boring. Spam can be a valuable part of any forum as long as it doesn't get out of control.