I just responded to a post and noticed that it was posting as a wiki? Is this new? Where is this being saved?
I believe the feature you are referring to is the ability to treat your post as a wiki, which means others signed into the community can edit it. I assume that would be useful if you have part of an answer and others could improve or add to it.
Interesting; however, I am not sure how I activated the wiki option? It must be new tho since I never saw the extra icon before.