When sending email messages, its easy to get in a hurry. But, remember theres a huge difference between dashing off a note to a friend and sending a message to a customer or colleague.
When sending email in a professional environment, the message should be professional. And, that includes using proper punctuation. (Phooey! You were hoping Id say you could break all the rules, werent you?)
There is one area of email that gets a little foggy. This is the rule that deals with punctuation at the end of sentences (e.g., periods, question marks, exclamation points).
In typed letters, there are two spaces after the punctuation at the end of the sentence. This originated from typewriters, which needed this space to create a distinct break between two sentences. Computers allot space proportionally. So, a break can be created with only one space.
In emails, you will see two different formats. Some people will use only one space after punctuation that ends a sentence. They will also use only one space after colons. Other people still use the two spaces.
Example
Those who prefer one space consider those who use two spaces to be...