shortlink is the use of a short-domain to create (usually with a third party link shortener service) a link that redirects to (often much) longer link, popularized on Twitter, and a subset of which are first-party permashortlinks for indieweb POSSEing and other use-cases.
See: URL design, especially:
- URL design: Avoid long links for reasons to use shortlinks, especially when posting places other than your own site.
bit.ly is a third party link shortening service that has been around for a while (since when?)
- for a long time you could use "j.mp" for bit.ly paths to shorten the link even shorter by two characters, and avoid using the restrictive .ly ccTLD.
See https://en.wikipedia.org/wiki/URL_shortening#Notable_services for a longer list that does not need to be replicated here (unless there is some IndieWeb-specific use or criticism).
Flickr has a first-party only short domain at:
that appears to redirect any non-empty paths to www.flickr.com
YouTube has a first-party (only?) short domain at:
Third party shortlinks (especially those that store the actual URL in a database and use an opaque identifier instead) have a reputation for fragility, and periodically result in a massive number of links breaking on various services that use them.
E.g. defunct 3rd party short-link services: