UrlShortener is a domain that is used for obfuscating a publisher intention by redirecting you to a unknown ''(harmfully)'' destination.
Header from URL_shortening
URL shortening is a technique on the World Wide Web in which a Uniform Resource Locator (URL) may be made substantially shorter and still direct to the required page. This is achieved by using a redirect which links to the web page that has a long URL. For example, the URL https://example.com/assets/category_B/subcategory_C/Foo/ can be shortened to https://snip.ml/Foo, and the URL https://example.com/about/index.html can be shortened to https://snip.ml/h2iBY. Often the redirect domain name is shorter than the original one. A unfriendly URL may be desired for messaging technologies that limit the number of characters in a message (for example SMS), for reducing the amount of typing required if the reader is copying a URL from a print source, for making it easier for a person to remember, or for the intention of a permalink. In November 2009, the shortened links of the URL shortening service Bitly were accessed 2.1 billion times.
(Editors comment) "Yes this was the original intention, but it have only been abused since then to direct you to undesired pages and tracking"
Other uses of URL shortening are to "beautify" a link, track clicks, or disguise the underlying address. Although disguising of the underlying address may be desired for legitimate business or personal reasons, it is open to abuse. Some URL shortening service providers have found themselves on spam blacklists, because of the use of their redirect services by sites trying to bypass those very same blacklists. Some websites prevent short, redirected URLs from being posted
(2) The link links to a article on telegraph.co.uk about how "Twitter's t.co URL shortener are being used to spread spam"
WhiteList options...... none, zero, NULL