"Can the Webmaster confirm what to do or not do, and how, and when?"
Please just report it and don't reply to it.
Getting multiple reports about a post is not a problem for us, though I appreciate that part of the intent of replying is so that others don't need to use their time to report it. Still, please don't reply. We've tried to make our reporting process super fast and easy so that it's not a big deal and doesn't take more than a few seconds as you move about the forum.
It's mostly for behavioral reasons, but our guideline about not responding to guideline violations is inclusive of these scenarios. It's less about somehow becoming a victim as a result of saying "reported," and more about giving any signal that their thread has found some sort of traction. Keep in mind every reply bumps the thread to the top of the message boards. Let spam or suspected spam slide down the message board, and let us review and clean it up.
Thanks also for the notes about other ways to handle it. Many of you have been here so long that you probably haven't noticed that we've significantly tightened the screws on new accounts. I'm not giving any details here as I don't wish it to be publicly posted, but it's there.
Empowering other forum members as moderators is still a nice idea, but it requires an expansion of our admin system and additional oversight. We may get there someday, but we don't have the kind of volume to necessitate it at this time. Also, we sincerely appreciate the help we already get from you in your reports, and to some extent we don't want to put any additional burden on anyone! This community is pretty great in how it looks out for each other.