So what if it's email? You can use DRY method and answer to it publicly. I hate personal inefficient communication. If documentation lacks thing being asked, update documentation. Don't answer the mail. Of course it would be more efficient to handle these tickets using community than just one developer. Answering queries publicly isn't as good method than updating documentation. Depending from situation fixing program and usability is still better option than updating documentation. I hate extensive documentation when updating program version, if it could be done efficiently by automated script / proram. I've been preaching about and utilizing this methodology last 15 years.