Computer security company Symantec highlights just how easily shortened URLs can direct users to malicious sites and software in this video.
Most Lifehacker readers are probably savvy enough to avoid these sort of traps, and as the post points out, this problem isn't the fault of Twitter or of URL-shortening services; it's a problem that could easily fool a lot of people. (The post is also quick to point out that "If you're running Symantec antivirus software, there's no need to worry", naturally.) So be aware, and be careful out there!
Firefox users, we suggest installing something like previously mentioned Long URL to expand those shortened links to give you a little bit more context before you click through. [Symantec via TechCrunch]