Why would a fashion magazine's site permit a pet training site to create a link to it? This means you couldn't register, for example, domain.uk.
Users can create these short links through the web interface at goo.gl, or they can programatically create them through the URL Shortener API. This sounds like a lot of work if you want to track all your outgoing links.
The trickiest part of tagging links in an email is coming up with a consistent naming convention for each variable. Example for event tracking using the newer API:
Want to take your link tracking to the next level?
Assign Parameters: Here is where you assign the tag’s Category, Action, and Label.
See if you are using Classic Analytics (ga.js) or Universal Analytics (analytics.js).
Even more Info Around
Url Shortener Hacking With [World Class Example]