Frequently in some public channel (such as Market, New Player or Dragon) I'll see a player ask a question about either the location of something, or wanting to purchase some player-made item. Oftentimes the question goes unanswered simply because no one then in the channel knows the answer, or no one has the crafting skill necessary to make the item. Occasionally, the lack of a prompt answer will spark some heated remark from the original questioner (e.g. "HELLO! ANYONE OUT THERE???").
So my query is this: Is it incumbent upon the other players in the channel to pipe up promptly with something like "Sorry, I don't know" or "Sorry, I can't make that," or should the original questioner understand that silence means that no one has the information sought, or can make the item requested?