Typing shortcut for a turtle emoticon on MSN Messenger. So if you type (tu) in the box and press enter, a small picture of a turtle will appear. I think it only works on version 6 or higher though.
(On an MSN convo)
Harry: What's your fave animal?
Elaine: A turtle!
Harry: What do they look like then?
The awkward turtle.
Person 1: I saw this really fat person in the co-op today!
Person 2: Hey, that's my mum!
Person 1: Oh (tu)