Bitly is a practical tool for producing short URLs to share in location of long URLs. Some people use Bitly to attempt to mask URLs to attempt to get you to click on dubious links.
The trick is to simply include a “+” to the end of any Bitly URL. When you add the “+” the URL will redirect to Bitly rather of to whatever the original URL was. That will then reveal you the Bitly page on which the reduced URL is hosted and will show you what the initial link was..

Ive created a number of brief video presentations of how this technique works. This is the Instagram video that I made about it. This is the YouTube video that I made about it.

You can try this with my Bitly link of.
bit.ly/ 2ZZnuP2 which will take you to the registration page for my Practical Ed Tech Newsletter (.
https://practicaledtech.com/weekly-newsletter/). If you attempt the same link but add “+” to the end of it so it checks out like this.
bit.ly/ 2ZZnuP2+ you will go to the Bitly page where I reduced my initial URL.