You have found a paradox.

I see what you're saying, but I feel the difference is that most of the time people who bring up a topic that's been discussed before don't add anything new to the discussion. Thus, they could have seen the previous discussion by searching, so threads that repeat a discussion are in a way similar to necros.

So with regards to discussing something that's been discussed before: maybe search first, and if what you were going to say isn't in the first couple pages of results, then start a new thread?

If you just post to say something like "necro" or "hi", then your post is viewed as not contributing. Think about what the thread is saying first then type what your going to post. In this way you are organizing your thoughts. Or if you cannot clearly organize what you are going to type, ask if the someone can summarize or clarify what the OP is saying.

Its appropriate to go onto a thread and necrobump it with a sort of "Necrobump! But this is still relevant!" Or to make a thread acknowledging your uncreative nature with something like "I know someone has probably asked this before, but I would like the information still because of X." But have a reason to do so.

It is not appropriate to make threads asking questions that have been answered several dozen times, or to bump threads for no reason. For instance, don't ask "Voltedge or Combuster" unless you have something new and "big" to bring to the table. Kind of like a- "I found X way to use combuster, and Y way to use voltedge; has anyone else found them out?"

I made some guides for things to think about before creating a new thread of necro-posting.

http://forums.spiralknights.com/en/node/76221#comment-665979