Not that I feel its my job to 'defend' Twitter - but as the current Number 7 in the Top 20 of Twittering Clergy and Bishops....

The thing to remember is that Twitter isn't meant to 'replace' Facebook or Forums, it's something else entirely. It's not for everyone, and nobodsy should feel in the least bit bothered about being on Twitter if they don't fancy it
However, I find it useful - subject to the following caveats and 'tips'
1. It's a bit pointless until you get a decent group of followers / following - by which I mean genuine people who share your interests. I'd say that it only starts to get interesting once you get 50 followers or more
2. You need a 'follower list' that is credible. I only follow people who are pastors, ministers, Christian leaders, Christian authors etc - and actively 'block' anyone else. As a result my follower list is very closely attuned to my interests. I haven't got time to waste on people who don't interest me!
3. It's almost essential, and certainly once you get a lot of followers, to use a Twitter cleint such as Tweetdeck, Seismic or similar. This enables you to quickly group people into 'lists' and makes following people feasible. Don't ever base your Twittering on the Twitter website - its hopeless!
4. The idea that Twitter is about telling people you are just about to clean your teeth or go to the bathroom is a bit of a false stereotype - frankly, anyone who tweets that stuff should be 'unfollowed'! There are plenty of interesting people around to follow, woh will share links, useful sites, ideas, ministry tips etc.
5. Tip : as a first step go to
http://www.twurchofengland.org.uk/ - the gathering site for CofE clergy who are on Twitter. Follow everyone on here! Most will follow you back, and you'll start to make friends and get value from Twitter
In short, if it is leveraged quickly, then it is a really useful ministry resource. But it takes a bit of time to set up and get working properly (once set up, it runs itself) and ,as I said, its not for everyone
BTW, if anyone wants to follow me, Im here
http://twitter.com/paulwalker71