There can be many IPFS Folder Hash's corresponding to different collections of pages. One for the global name space (which may also be refered to by a mutable IPNS hash), and others for particular collections on pages sharing the same title/slug.
What this means is that without a database, and only with a single mutable top-level hash, it is possible to direct wiki to serve a global writing space.
For instance say we want to write another wiki page about cats on a personal wiki I own at "my.wiki" then if there is no existing page the client can request a list of pages named "cats.json" from the following IPFS directory:
Mutable IPNS Hash/cats/
or go back in time, or look at another context by listing the directory contents of a specific snapshot of wiki in an IPFS folder named:
Another IPFS Folder Hash/cats/
Similarly we could look at different collections of wiki pages analogous to authoring within different neighbourhoods - simply by pointing at different top-level IPFS folders.