Shoutbox

Hi.
Can someone help me?
I'd like a simple plugin that adds one code that shows a number that everytime that is posted increases it in One.
Example:

Name said:
Hehehehe - laugh x 1
Other said:
hm.....
Name said:
Hehehehe - laugh x 2



Where the numbers would be a variable that increments itself.
Is that possible?

Thanks for reading my question and sorry for the bad english, I don't speak english very well ^^