Since I added the Twitter widget to this blog, in an effort to become au fait with one of the newer social channels, I find it's impossible to comment from a pad/pod/iPhone.
Luckily none of the regular commenters here seem to be using Apple devices, but I like to be able to reply. So I'll have to start using a PC again. In the long run I may eventually have to remove the twitter thing if I can't fix it. Anyway, I mostly use Twitter to read (people like Stephen Fry and Richard Dawkins, as well as Scottish folk I know), not to tweet.