Clicking on links that different people send can often be a cross-your-fingers experience, considering that there are malicious tricksters, unknowing victims, and hijacked accounts to watch out for. So Twitter's attempting to make the experience less dangerous by checking (and sometimes rewriting) the links found in direct messages and email notifications.
Del Harvey, Director of Trust and Safety at Twitter, explained on the official corporate blog, "[W]e'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."
Harvey later continued, "For the most part, you will not notice this feature because it works behind the scenes but you may notice links shortened to twt.tl in Direct Messages and email notifications."
This move is bound to ruffle a few users' feathers - changing the text in private messages is a sort of bold step - but on the whole, it should prove welcome enough. A safe environment is in just about everybody's best interests, from regular users to marketers to Twitter itself.
Let's just hope the new feature works well and doesn't create a false sense of security.