Update: Added comment from Twitter below.
If you are user of the popular clients for Blackberry, iPhone or Android; UberTwitter or twidroyd for Twitter, you might not be able to use those applications for some time now.
We have suspended UberTwitter and twidroyd for violating our policies.
Every day, we suspend hundreds of applications that are in violation of our policies. Generally, these apps are used by a small number of users. We are taking the unusual step of sharing this with you because today’s suspension may affect a larger number of users.
Twitter has officially suspended the two clients for violating of policies. So UberTwitter and twidroyd users will no longer be able to access their tweets, replies or messages and update their statuses.
We are committed to helping you continue to use Twitter during the disruption of these applications. You can download Twitter for Blackberry, Twitter for Android and other official Twitter apps here. You can also try our mobile web site or apps from other third-party developers.
The Next Web found the note which was posted on the Twitter support blog, where Twitter suggested that users of these clients use another app for their Twitter needs. Though the note mentioned that these clients were blocked for policy violations, there was no updates on what policies they had violated.
Nevertheless, lot of Blackberry users will be left out in the cold because UberTwitter is one of the most popular clients. You could switch to the official Twitter client for Blackberry for now till this issue is resolved.
We have emailed Twitter for more information and will update this post as soon as we get any updates from them.
Update: Twitter spokesperson Carolyn Penner responded back with a comment
We ask all developers in the Twitter ecosystem to abide by a simple set of rules that are in the interests of our users, as well as the health and vitality of the platform as a whole.
We often take actions to enforce these rules; in fact, on an average day we turn off more than one hundred services that violate our API rules of the road. This keeps the ecosystem fair for everyone.
Today we suspended several applications, including UberTwitter, twidroyd and UberCurrent, which have violated Twitter policies and trademarks in a variety of ways. These violations include, but aren’t limited to, a privacy issue with private Direct Messages longer than 140 characters, trademark infringement, and changing the content of users’ Tweets in order to make money.
We’ve had conversations with UberMedia, the developer of these applications, about policy violations since April 2010, when they first launched under the name TweetUp a term commonly used by Twitter users and a trademark violation. We continue to be in contact with UberMedia and hope that they will bring the suspended applications into compliance with our policies soon.
So it looks like UberTwitter violated several rules including trademark, character limits and making money by editing tweets.
Update 2: Left out in the cold, check out some UberTwitter alternatives for Blackberry and Android.