I believe this to be a notable post. Do what you people do best.

Twitter.

If you click Donald Trump's latest tweet (pic related) it has Vote.GOP, which is a link

If you click it, pay close attention to the lower part of the browser. It goes through quickly a t.co link.

Twitter controls those short-links.

And tracks them

see: https://www.siliconrepublic.com/enterprise/twitter-dpc-gdpr-tco