Anyone can revert vandalism and bad-faith edits, but it takes a couple of clicks in the page history to get it done. Users with the "rollback" permission are able to undo bad edits with one click, by using the rollback link on diff pages, user contributions list, or the list of recent changes.
It is important to note that admins (including bureaucrats) already have rollback rights by default. Users with rollback rights are just users who are not necessarily an admin. Rollbackers (users with Rollback rights) can be seen via Special:ListUsers, but they do not by default have any special title that appears on their userpage. http://disney.wikia.com/wiki/Help:User_access_levels#Rollbacks
Rollbacks are users to contact when Admins aren't around and you spot vandalism. They patrol Special:WikiActivity a lot to be able to spot vandalism easily.
All Administrators automatically have Rollback permissions. They will not be listed here. Also, most Chat Moderators have Rollback rights. They will not be listed here either. To see a list of Chat Moderators please visit ------------------------. To view the list of Rollbacks visit http://disney.wikia.com/wiki/Special:ListUsers?group=rollback.