Actually, there is a pretty nifty trick if you want to dereference (preview) a shortened goog.gl link (that was created using the Google URL shortener) in order to make sure that it isn’t linking to something dodge like 9gag.com.
To see where a shortened goo.gl link points to, paste the shortened link with a plus at the end into your browser and hit go. (So if link is http://goo.gl/KDQsVr enter http://goo.gl/KDQsVr+ into your browser.)
Google will then bring up an analytics page showing you the link, how many times it has been clicked on, where it points to, as well as the associated QR code. It even has stats on referrers, browsers, countries and platforms.
Very useful indeed, and apparently this trick works for bit.ly shortened links as well.
Outside of that, there are also a number of websites out there that perform the same function, longurl.org for example being one of them.
Related Link: https://goo.gl/