I've found that many teachers don't know how to shorten their URLs to put them on presentations or handouts. I recorded a 60 Second Tip tutorial about how to shorten your hyperlinks.
If you're using QR Codes
Note that before you shrink a hyperlink using a QR code, it is beneficial to shorten the link (if the QR code tool doesn't do it for you) so there is less information encoded and you don't have an overly large QR code.
Test Shortened URL's because some Schools Block them
Also note that some school's firewalls block link shorteners because they are easy ways for hackers to hide their links. (Don't click shortened links in most emails or direct messages, for example.) If you use a reputable QR code shortener like bit.ly or tinyurl.com you should be alright.
This is a must-know skill for teachers and students alike because it helps us communicate more easily.
Why use Tiny URL instead of Bitly or other choices?
The reason I use tiny url for links for my students is because I can choose a word or class code as part of the link. I store these in my Evernote lesson planning notebooks so I can use them next year. The links are just easier to see on the board and type in if meaningful words are part of the link.