1. I'd use a library or framework that handles the interactive parts, which should make it fast to implement. We have tools to help make other tools.

2. A tool's popularity/usage could be a way to judge when it's worth the effort to add this sort of system.

3. With the Etsy approach, I would also be wary of the cost of interruptions. Getting constant Slack notifications is not conducive to getting work done. You could silence them, but then what if someone can't move forward without getting an answer to their question?

4. There is a nice balance to be found between wasting time documenting everything possible upfront and not documenting anything until someone asks a question.

5. Personally, when I find documentation that needs to be updated, it's usually as simple as editing a wiki or editing Markdown and making a pull request in GitHub's interface. To me, that's not much effort.