A perfect example would be the post by a TF beek - Ask questions here(I think). I would post a link but I can't find it now. The purpose as spelled out by the OP was anyone interested in TF could ask questions about the subject and he would answer them. I have to give Mr. Parker credit for trying to keep it on track but it was sidetracked, interrupted, you name it.
My point is:
The OP should be respected. Why not just begin a new post to suit your needs?
I have noticed that most of the off topic posts begin with a disagreement that gets batted back and forth or meanders where ever it will and does nothing to progress the OP.
While it may be entertaining(sometimes), I find I would rather not post than wade through all the unrelated mess. I find it hard to believe I'm the only one to feel that way.
Who should judge? Can we all just agree to make an honest effort to stay on topic? Police yourself, more often than not one knows when it happens.