A Note About Email Business Letters. It might be tempting to leave out the closing when you're communicating by email, but don't give in to that temptation. Although no_closing emails are perfectly fine for everyday communication with your friends and teammates, they'll seem brusque – or worse, unprofessional – to people you don't know as well. You should also use a business letter closing when you're corresponding with someone professionally about an important issue, whether it's a new project or a job opportunity.
There is a tendency to think that the often arbitrary rules of letter writing don’t really matter, that as long as your recipient can work out what you’re saying, that’s good enough. This shows a great deal of disrespect for your recipient, though, and for your own ideas. It suggests that a) your reader’s time isn’t valuable enough for you to write clearly and efficiently, and b) that you don’t particularly care about the content of your letter.