McCulloch did a couple follow-up polls, too, asking the same question if the exclamation point was at the end of a sentence, or if it was sent just on its own. This is how that sort of language creep happens.
If you are guilty of overusing then consider how you can replicate the exclamation mark in other ways. What's noticeable is the change in the rate of use.
Consider how your reader may interpret it when she reads it. Only use it to emphasize something that is vital to the content. Punctuation should be clean and simple, there to guide the reader through the document and to add clarity to the message. As Humphrey points out, there are better ways for everyone—regardless of gender—to convey sincerity and warmth than resorting to vague punctuation.
As a writer at the Chicago Tribune recently observed. Eventually, most people seemed to stop resisting their rise. That's right, I did. You should be doing this anyway, but it bears repeating: always use proper grammar in work emails.
Cory writes for Fast Company's Leadership and Entertainment verticals.