Exclamation marks are ridiculously overused IMO. It’s an epidemic. If people spoke the way they write their status updates on Facebook or their tweets, we’d live in a world with an unacceptable number of folks who spoke like super-excited 4 year old cheerleaders at a Bieber concert with their new puppy.
Lots of people also like to use multiple exclamation marks. They seem to think doing this makes their statement more pronounced, but what it really does is make their ridiculousness more pronounced. Here’s a good rule that I learned in grade two; use one exclamation mark. Same goes for question marks. One is enough to communicate that a string of words is a question. 12 question marks indicates that you’re an overly inquisitive cretin.