Don't know if this is the right place to answer this question, but I'll try it:
I've now the "privilege to edit community posts"; moved by curiosity, I opened the link to understand what exactly they are, and the first paragraph says:
What are Community Wiki posts?
Community wiki posts are more easily editable by all users, and do not confer any reputation.
That is not exactly what I would call a definition :D what are community wiki posts? Every answer to a question is a community wiki post? Or only some of them with particular characteristics? And moreover, is it me that don't get it, or should the answer I posted be clearer?