Email Salutations

I received an important email and replied to it. What I forgot was a salutation. You know, "Dear Mr. Doodledoo, " Forgetting that salutations are good manners, I messed up. It's a good thing they contacted me again.

Then I started thinking. How do we make a salutation in the digital age? In school (back when we still used pen and paper), we wrote:

 Dear Mr Doodledoo, 

This salutation has been kind of the standard. This is written neatly above the message body with an empty line before the message body. These days, it feels kinda weird. You don't say dear to just about anybody, and it comes across as too formal.