Twitter growing pains continue to annoy users

Once again twitter users have been suffering through the growing pains at http://twitter.com. This time it's an issue where updates from people you are following might not appear in your personal timeline.

I've experienced this, but the interesting thing is that these updates do get delivered to my instant messaging client. Twitter has not issued an ETA for the fix, but they are making assurances that nothing is being lost.

Users have become accustomed to intermittent service losses at twitter. Usually through short lived outages. However twitter did experience a serious outage recently when Amazon's S3 service experienced an outage. Twitter leverages S3 to host a number of user assets including user profile background images and avatars.

Update 1: Twitter says they have identified the issue and are taking steps to resolve it. Still no ETA.
Update 2: Looks like things are now back to normal. But how long will it be before the twitter user base moves to the likes of the likes of Pownce or Jaiku? It's by virtue of the fact that there are currently so many A list people on twitter that the service is still popular, but what happens when they leave?