So this is a “How would you handle it?” question.
I have a customer support forum and had a person come on the forum and post a very legitimate question, the question was promptly answered and the post was buried as is natural. Eight days later this person came back and edited his post replacing the contents with a Vietnamese gambling site, but it wasn’t caught for a nearly 2 months. Since this wasn’t the last post, the thread didn’t get bumped and brought to anyone’s attention. Does anyone have ideas on how one might combat or keep on top of this type of behavior?