The Mezzanine

I very rarely write letters at work these days, but would stick to the Dear Mr Smith format to someone out side the company. Internal letters would be Dear John.

With email I generally just start with 'hi' rather than Dear John, or no salutation at all. The tone of the email would vary depending on whether I know the person or not and whether they are internal or external to the company. And always stop and think before pressing the send button.