Robert is an experienced wiki user. He regularly reads and contributes to several different wikis, with different communities of people, different engines and different organisation.
He sees both the common elements of the wikis he uses, and their subtle differences. Asked "what wiki engine is best" answers "best for what?".
He knows the basics of the formatting rules of all the wikis he uses, but doesn't care about most of them. He developed several habits that allow him to write good and easy to understand text without using markup elements that are uncommon. Occassionally he will use markup that doesn't work on the particular wiki -- he hates that. In such a case, he will either edit the page again and correct it (or convert to markup-netral form), or let it be if it's nothing important and the meaning can be guessed.
He doesn't correct other's contributions unless there is an obvious error or he is refactoring a page. Sometimes he will ask administrators of particular wiki to include some additional markup that he considers useful.