You can even see when the other party is typing and read your message.

First find his facebook id. You can do it at http://findmyfacebookid.com/ or any other service.

http://www.facebook.com/othelis ---> id= 699313289

Open you browser's console at facebook and type

Chat.openTab(id) eg. Chat.openTab(699313289)

You can live chat with strangers and non friends now and get notified when they read your message!