I've been working on new end-user documentation for Solar, both for the general principles (in the Main area) and for the various classes (in the Solar* areas). You can see the results of these efforts here:
One of the really nice things about using YaWiki for end-user docs is that you can very easily link to methods and properties of other classes simply by typing the name of that element. For example, typing "Solar::get()" automatically links to the page named "get()" in the "Solar" area of the wiki; similarly, typing "Solar::$config" goes to the "$config" page in the Solar area. No need to remember a complex hierarchy of pages every time you want to reference a method or property, as with (say) DocBook. ;-)
To get that auto-linking behavior, I created a custom Text_Wiki rule based on the default Interwiki rule. In that custom rule, all I did was edit the regular expression to accept double-colons as the area/page separator. Then I told YaWiki, via the config file, that custom rules were in a specific directory. Voila: auto-linking of class-named areas with pages names for methods and properties.
So, who says wikis are not for documentation? ;-)