When should you use an exclamation point at the end of a sentence?

This is an exclamation point: 

!

When should you use an exclamation point at the end of a sentence? The answer is interesting because the way that it's used has actually changed quite a bit in the last 10 years.

The old rules

Here's how exclamation points have traditionally been used in writing:

• Put one at the end of a serious written warning.
  

  Do not touch!

• Put one at the end of an angry statement.
  

  I strongly disagree with that opinion!

• If you're quoting what someone said, use an exclamation point to show that the speaker was excited, surprised, or angry.
  

  He said, 'Wow! I can't believe it!'

Here are more detailed rules for using exclamation points in formal writing:

http://www.whitesmoke.com/exlamation-point-usage

How English speakers use exclamation points now

In the past few years, we've started to do a lot more informal writing because of email and social media. This has changed the way that people use exclamation points.

Now, a lot of English speakers use an exclamation point to show a friendly tone. It suggests that the writer is smiling. Here are some examples from real-life Facebook status updates:

Happy Valentine's Day to all my FB friends and family!

Good game Giants! You came out and played better than most expected!

Yay! See you there!

Ran in the Break-a-Leg 5K this morning!