When you write a Phriction (wiki) document and use markdown 'header' inside it, there's a nice little ToC generated ([[https://secure.phabricator.com/w/changelog/2011_10_october/ | example]]).
Diffusion also has a nice feature about rendering readme[.md/.txt] inline with directory listing ([[https://secure.phabricator.com/diffusion/P/ | right there]]).
It would be cool if the same table of contents was generated in 'diffusion' as well.