We have been hearing from a few users about their legacy Twitter apps which stopped working last night. This is not an outage but rather Twitter disabling/retiring their much less restrictive APIv1 as it moves up to their new APIv1.1 that newer Twitter clients use. The new API has some serious limits which has more or less killed off the third party Twitter app market. Either way there are still a few older clients that have not been updated to make use of the new API.
If that is the case with your favorite client then you may want to try to reach out the the developer but you may not have much luck. If they planned on updating their app they would have done so by now.