Considering it's a forum and there's hardly anywhere else to make a proper announcement, I think it's just fine to have a thread made of it, and once it's served its use it can be disposed of, simple as that.
What I'm saying is that this isn't the sort of thing you should be chastising people for. They can use the forums/IRC in whatever non-rule-breaking way they want. It seems like it would be better to just ignore it. It's not like it causes any problems.