See explanation Yuri Khan has made earlier.  My package, like said in
comment, makes a request for a URL produced by concatenation of
shorten-url-base with a URL passed as an argument and inserts data returned
in response in current buffer.  It's up to web server to produce shortened
URL.
The idea is that for example https://clck.ru/FHyra may look more nice than
http://global.espn.com/football/blog/transfer-talk/79/post/3789639/live-transfer-talk-manchester-uniteds-100m-battle-for-jadon-sancho-with-psg
Consider that people you're chatting with may use smartphones and long
links would look nasty on small screens.

On Sun, Mar 3, 2019 at 6:00 AM Richard Stallman <rms@gnu.org> wrote:

> [[[ To any NSA and FBI agents reading my email: please consider    ]]]
> [[[ whether defending the US Constitution against all enemies,     ]]]
> [[[ foreign or domestic, requires you to follow Snowden's example. ]]]
>
>   > > Is the shortened URL expanded locally inside Emacs?
>   > > Does it refer to a real website?
>
>   > Of course it refers to a real website, the idea is that you can use
>   > shortened URL in chat so the people you're chatting with could use it
> too.
>   >  "what made that choice desirable?" it's working and it suits me well
> :/
>   > shorten-url-base is customizable.
>
> Now it is starting to make sense, but it presumes that the shortened
> URL is defined on a web server, not just in Emacs.  Does your package
> set up the definition too?
>
> That wasn't clear to me when I read the first message.
>
> --
> Dr Richard Stallman
> President, Free Software Foundation (https://gnu.org, https://fsf.org)
> Internet Hall-of-Famer (https://internethalloffame.org)
>
>
>