ContentAltnernageek, TechCrunch and others are reporting, and Biz is confirming, that T-Mobile is restricting/denying access to Twitter.
According to Alternageek, T-Mobile’s customer service department wrote:
T-Mobile would like to bring to your attention that the Terms and Conditions of service, to which you agreed at activation, indicate “… some Services are not available on third-party networks or [...]