I have been a fall of twitter for sometime now, but they are having serious problems due to their architecture .
(See here Twitter Technology Blog: Twittering About Architecture). I hope they get it resolved soon, before it is too late.

I have also been a fan of tumblr for some time too. So I thought it was interesting that twitter is updating their
Twitter Status using tumblr. Perhaps more people will start using tumblr as a result. Tumblr is great and worth considering.