Twitter’s Matt Harris, on the DM thing:
All of this information has helped us to improve the OAuth flow for you and your users. But, we know that we’re getting close to the DM enforcement date and that some of these new features aren’t available to you yet.
We understand this means you might not be able to fully test your updated flow so we are going to extend the deadline until the end of June.
This makes the new enforcement date Thursday, June 30th, 2011.
This whole thing really makes Twitter look like a bunch of amateurs.