Here’s what I see:

Something Bad Has Happened At Twitter

Twitterrific users are currently unable to access the service via the iOS app. As of this writing we have heard nothing officially from Twitter and are trying to learn more. This may just be a temporary bug; it may be more a more serious issue.

As soon as we know more we'll update this message. We thank you as always for your support and patience as we work through this problem.

- The Iconfactory Team