I know there are 5 different answer flags:
spam
Exists only to promote a product or service, does not disclose the author's affiliation.rude or abusive A reasonable person would find this content inappropriate for respectful discourse.
not an answer This was posted as an answer, but it does not attempt to answer the question. It should possibly be an edit, a comment, another question, or deleted altogether.
very low quality This answer has severe formatting or content problems. This answer is unlikely to be salvageable through editing, and might need to be removed.
in need of moderator intervention A problem not listed above that requires action by a moderator. Be specific and detailed!
When should I use each of these - example questions would be useful, including what not to flag. What should be done with link only answers and really badly formatted ones would be nice too.