There is a feature called suggested tags where the software suggests some additional tags depending on what is already written.
Originally I thought that they are only enabled on Stack Overflow, SO meta has several posts tagged (suggested-tags).
But then I noticed that:
- Probably they are also on language variations of SO, judging by the screenshot shown here: Edit a post in mobile web immediately displays suggested tags.
- This post mentions that they are also enabled on Meta Stack Exchange: Enable suggested tags on other sites. And I was offered suggested tags also when I was going to choose the tags for this post.
- The tag (suggested tags) exists also on Ask Ubuntu meta.
- I have now found a question showing a screenshot with suggested tags on Ask Different Meta.
Question: On which sites are suggested tags enabled?
Here is a screenshot showing suggested tags which I was shown when writing this question. (Although I am not really sure when they appeared - whether it was only after the body was long enough.)