Once in the inbox, a columnist can decide to delete it, answer it, or leave it in the box. I tend to answer most questions - as long as they are a specific question. I rarely delete questions, unless it appears that the same person has asked the same question multiple times while waiting for a response.
I keep other questions in my inbox - ones that may not be questions but are more like stories, ones that I need to research before answering, etc.
The columnist is solely in charge of what happens to these questions, and as you pointed out in a really interesting note you left me, some people answer quite quickly and others don't. I tend to answer questions whenever I am online, though that can sometimes be rare as I am quite busy.
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