How to float the table of contents to the right with MediaWiki

A TOC in Wikipedia is only generated if the article has more than three sections. The one you linked to only has three, and so it is not generated.

If you were to add __TOC__ or __FORCETOC__ to the document a TOC would be generated. __FORCETOC__ causes the TOC to be placed before the first section heading, which would be before "Publications", while __TOC__ will cause the TOC to be inserted wherever it was placed.

For more information you might want to look at WP:TOC, which goes into more depth on how TOCs are generated in Wikipedia and how to control them.

It seems that the Special:ListUsers page is standard functionality but only with a later version of MediaWiki than what we currently have.

Wikipedia, for example, does have this particular functionality in place.