This still exists: http://stackoverflow.com/privileges/community-wiki
What is meta?
- Any Stack Exchange user can ask a question
- The community provides support, votes on ideas, and reports bugs
- Your voice helps shape the way Stack Exchange operates
Yes, the heading "When should I make my answers Community Wiki?" should probably read something like "How are questions and answers made Community Wiki?". Also, the part about automatic conversion would fit in here.
Lastly, the screenshot should be updated (or it should be made clear that this is how it looks for moderators — if that's the case ... I have no idea).