I find twitter a real bonus. I've tried plurk which seems quite good too. I particularly like the way the group in IET (Institute of Educational Technology) have got together and now share alot of information in bite-sized chunks. Oh, and of course I just love the personal statuses - rather like Facebook statuses which are my favourite bit of facebook.
I like that I can hook up twitter to my igoogle which is my home page ... and from my igoogle using the betwitter can link to twitter and then using the twitter application in facebook link to the my facebook ... pretty much - one update - updates all .... if only I could figure how my google chat could work with twitter :D