I don't work on the API team, and normally don't respond to REST API questions, so please bear with any inaccuracies:
I haven't heard anything about Twitter explicitly turning application registration off. I believe that all parts of Twitter.com should be working correctly -- albeit sometimes slowly or with timeouts or with 503s... but everything should be working. I've escalated the app registration issue to the API team. I cannot offer a response time as I don't know what any of the issues are or what the priority would be for fixing this problem. It might be helpful to have a detailed trace of a failure or two sent to a...@twitter.com should a resource become available to look at this issue. -John Kalucki http://twitter.com/jkalucki Services, Twitter Inc.
