What are the proper guidelines for reporting another user?

There are currently three reports you can make for a fellow user:

* spam

* abusive

* offensive content

How long after a user posts content that fits any of these should he/she be reported? What portion of the content that the user posts should fit in the category for that user to be reported? Should you notify the user before reporting? If so, do you notify in order to prepare them for the report, or to somehow rectify their content to avoid a report?

This has come up for me after noticing more users posting spam articles about downloading copyrighted movies. Clearly the articles are spam, but the users only just joined Fanpop, and the only thing they've posted are these spam articles. Is it enough to report the articles as spam and then give the users a break that maybe they'll post acceptable content if given more than a day, or should the users be reported as well and sooner than later to avoid the possibility of more spam being posted to Fanpop?

That's the practical example, but it occurs to me that the same sorts of questions apply to cases of abuse and/or offensive content. When do we report the content and not the user, and when do we report both?