I use it constantly, i am on all day at work - i have a few ppl on my contacts (98% of whom i know) and i dontthink i could get through the day without that flashing orange rectangle letting me know that someone want to chat with me
i dont mind who puts me on their contact list.. im usually pretty chatty.
i love it for filling in time, gettin the goss.. looking at my O/Seas friends msn spaces and updating mine, i just like it. But i am 21.. so you could put it down to the SMS generation i guess..? also saves me money by talking to my brther in london.. other wise we would never communicate