I use "sir" or "ma'am" where appropriate as a jesture of respect. The only "dear" I use is in reference to my wife of 48 years. If I preface or suffix that term with colorful metaphors please don't tell her : ) I think the unusual use of prefixes like dear here are by people whose first language is not English and sometimes the @handle is not gender specific or maybe they take it for female. Just guessing...