I believe that the origin of the common text messaging 'lmmfao' - meaning 'laugh my mother f***** a** off' - originally came from me, approximately 10 or so years ago, when I still had dial-up, and I've been using it in chatrooms and everything. I had never seen anyone else use it until I had been for about 4 months. Then people started catching on.

Although, who knows. Maybe there's a particular origin for 'Laugh My A** Off' too.