I don't quite understand how the process of tag-creation works.

In [JavaScript text editing webapp](https://codereview.stackexchange.com/questions/35280/javascript-text-editing-webapp), I've added [overall-review](https://codereview.stackexchange.com/questions/tagged/overall-review "show questions tagged 'overall-review'") to the tags list and thought that I would be able to edit the wiki and such right away, but this is not the case. 

1. Do I need a certain amount of rep to create tags?
2. Does tag creation fall to the moderators?