I want to ask a question about what "hd tv boxes" do and which one I should pick from my cable provider.
Is there a SE site suitable for this purpose?
For anyone to answer this question correctly, you'd have to provide an overwhelming amount of information about your specific setup and needs. That would make your question "too localized" for Stack Exchange.
Alternatively, you could be less specific, but then you'd get less useful answers. Some would be based on answerers' personal experiences and all would involve some implicit assumptions. The question would devolve into a GTKY/poll post, which would be "not constructive."
So no, there is no suitable site in our network for your question.