As far as i know, all level 3 users can edit wiki’s. Even if that post is made by other person. For example, this reply is wiki, and available for edit.
Update: I have disabled wiki mode from this post, as i don’t want to keep an eye on this comment anymore (to ensure no one abuses it). I’m leaving all the edits below. Send reply if you want your comment removed from this post.
Edit: Wow I see no way this can be abused at all by anyone in existence. (edited by Xaron)
Edit2: looks like i get notifications for edits. Good to know! -KVKH
Interesting…
Edit 3: That’s legit. One could almost have a public chatroom on a post by simply editing in the next response (edited by Xaron)
Edit 4: I’m level 2 and I can edit it -Dr4gon97
Edit 5: IDK what level i am, but i can edit it too -VampirkoO
Edit6: Rip my inbox if this thread becomes popular. -KVKH
Edit 8: It’s not your usual post, you can’t edit others post in this thread for example -VampirkoO
Edit 9: I get what it does, but what can you use it for? - FaneL
Hello there - Morrov555
General Kenobi! -KVKH (yep, i’m fan of prequel memes)
Why can I edit this? Ivan
Because that’s how this wiki feature works. -KVKH
Edit10: Lohcke was here

Ooo. I found out how to shrink images 
<img src=[image/gif link] height=42>
The width scales to fit the image to the new size.
-Terranguard
Thank you for that, that’s actually feature i needed! -KVKH