Some services offer shortened URLs that also allow tracking of clicks and forwarding to a given destination.
These are very popular in various marketing circles, on social media, and online in general.
They’re generally no good, despite the ability to track clicks. It’s really an ethical issue of whether you show your visitor what they are clicking on, and the right thing to do is to show them. That longer URL often gives them lots of information regarding where you are taking them.
Here is a list from wikipedia on the various ways URL shortening can be bad: