Good information Robert...

Exclamation points are also called exclamation marks.

Here are a few simple punctuation rules governing the use of an exclamation point/mark:

1   Use an exclamation point to show emotion, emphasis, or surprise.

    (multiple points are grammatically incorrect)

2  An exclamation point replaces a period at the end of a sentence. It also replaces a midsentence comma.

3  Avoid using an exclamation point in formal business writing.

source:  http://www.grammarbook.com/punctuation/exclaim.asp