Can you clarify what you mean?
Do you want to just ignore the marketplace? How is that different from just choosing not to browse there?
Or, post on the marketplace, but no one else can know that you post there?
Not quite the same as ignoring individual threads, or posters.
I don't have any "watched forums", as I simply monitor new posts - doesn't matter to me what forum is used.
And, what about the times when a poster decides to start a thread in your ignored forum, but it was posted in the wrong forum - and, is delightfully interesting to you....(might happen!)
How would you ever know?