Okay, having done a negative, now on to the positives of using Twitter.
The social/professional mix is intriguing. People will post links and quotes, but also comments about their hotel room. I follow Scott Leslie, D'Arcy Norman and Brian Lamb, so feel as though I was almost present at the Open Education conference. I have found some good sites through people such as Guy Kawasaki (who I am convinced never sleeps, or is in fact an artificial intelligence program). I have also used it for work, sending someone a message who I saw was online and was supposed to be in a virtual meeting with.
But I've been struggling to get my voice right. I'm happy with Facebook status updates, I get the right tone, but I'm not sure whether I should be posting social chat stuff (I'm off to the cinema), or professional stuff ('Interesting post here') or self-promotion ('New blog post'). It turns out that it's all three probably, as Chris Brogan says in this interview. As with blogging, it's taken a while but I feel as though I'm finding the affordance of the medium now.
Which leaves the question - why? Particularly if not many people are hearing what I say anyway. For me it's about the potential. Next year I would like to get all my students to sign up, so they have this constant low-level contact which is much less intrusive than IM. I think it will be an excellent back-channel around the content. I would also like to see it used institutionally - if there was an OU twitter, it would provide a great knowledge sharing and social bonding mechanism. I'm perservering then, in the hope these come to pass.
So if you're not on Twitter, give it a try, I'll follow you. And if you tried it a while ago and gave up, give it another go, we can follow each other. You can follow me here: http://twitter.com/mweller