ShadyURL is most of the time a URL shortening service. On other occasions, it somewhat lengthens other URLs, especially the already short ones, just to accomplish its true purpose. It masks your links and makes them look suspicious and frightening.
Use it like most URL shortening service. Paste the URL you want and ShadyURL will generate a suspicious looking link to send to your friends. It will look as if you’re sending them a link to a malicious website which is enough to frighten a soul who is web literate enough to understand it. It’s great for scaring your friends especially if they’re asking an important link from you. It will make them think twice before clicking the link that you sent them.
Aside from the shady URL masking, you can, of course, use the service to shorten URLs and get less shady looking ones. Simply tick the “shorten (somewhat less shady-looking)” box and you’ll be able to generate a more decent short links than ones that contain a malicious_cookie word on them.
The service clearly states that it is for entertainment purposes only and the user is solely responsible for the content behind the links generated using the site. You also need to be somewhat cautious before sending the generated shady links for some of them can be offensive. All I’m saying is read the generated links before sending them even if it’s just for fun.