As regular follows will realise by omission, I am not a great fan of Twitter. With 90% of all twits being made by 10% of the Twitters, and 40% never continuing after the first few months, it is not surprising. But maybe, just maybe, there could be some good information to be gleaned from some of those Twitters. I have been looking for some time for a good overview. And here is the best so far, courtesy of Jane Hart.
Guide to Twitter