lol

... often just replaces a full stop in instant messaging.

It's roots lie in the abbreviation for laughing out loud, but in chatting it lost its meaning lol

May even replace other punctuation marks lol

That's a very ponderous comparison lol
But I know what you mean lol
I have a dream lol (replaced exclamation mark)
Do you want total war lol (famous game; rising tone supersedes the question mark here)