For the most part, URL shorteners should not be used here.
Their primary benefit—fitting long URLs into artificially scarce text spaces—is of no use here. The Question and Answer spaces are plenty large enough to handle 99.99% of all URLs. Even the comment space is plenty big enough for most.
On the downside, however, URL shorteners can be (and have been) used to hide:
- links with affiliate codes
Almost all URL shorteners should be fixed to be their target URL. The following links are to searches on the main site to find posts with these URL shorteners in them.
(Please add more as necessary.)
Note that URL shorteners in comments aren't findable this way.
Note also that some instances should stay. Explaining how to use an URL shortener, for instance, is okay. Use your best judgment.
As with all clean-up projects, don't just fix this one issue. More than likely there are other issues with the post that should be addressed.