Board Thread:Support Requests - Designing Your Wiki/@comment-4536091-20130810001927/@comment-3269579-20130810005602

Go to http://[your wiki name here].wikia.com/wiki/MediaWiki:User-identity-box-group-sysop and edit the text there: this will become the updated title on admins' pages.

Similarly, if you go to http://[your wiki name here].wikia.com/wiki/Special:AllMessages, then filter by prefix 'User-identity', this will bring up all the other things you can modify that appear on user pages, like the founder's job title, the wording where it says "My favorite wikis" and so on.