The goal is to release the work anonymously, but not into the public domain or as CC0, but rather under the Share-Alike licence. However, most of the licences require reusers to identify the original creator of the work, which they will be unable to do.
- Anybody can ask a question
- Anybody can answer
- The best answers are voted up and rise to the top
The route that most people take, is to release it 'pseudonymously' rather than anonymously. So you just make up a pseudonym and use that in the copyright/licence statement.
A better approach may be to use the little-known CC-SA 1.0 licence, which was unfortunately retired by Creative Commons due to it not being used a lot. This licence requires a reuser to publish their altered versions with the same freedoms, but does not place the requirement to find out who was the original author.