Twitter announced a new URl shortening service to stop the scams. Recently there were too many Twitter accounts got hacked using some url shortening services. From the announcement on twitter blog
Today, we’re launching a new service to protect users that strikes a major blow against phishing and other deceitful attacks. By routing all links submitted to Twitter through this new service, we can detect, intercept, and prevent the spread of bad links across all of Twitter. Even if a bad link is already sent out in an email notification and somebody clicks on it, we'll be able keep that user safe.
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