Link shorteners are bad for usability, but they're also a potential attack vector for targeted attacks. A link might go to the right site 99.9% of the time, an

Link shorteners are bad for usability, but they're also a potential attack vector for targeted attacks. A link might go to the right site 99.9% of the time, and redirect a user to a malicious site the rest of the time. You can redirect based on the browser fingerprint, IP address, or any number of things. I have a proof-of-concept of this at http://brokenthings.org/ http://brokenthings.org/ It redirects to a "friendly" site for preview scanners, etc., and to a "bad" site (Youtube videos, with some stale ones) for users. It's blocked by Facebook, but still works on G+.