1) Some form of file corruption (possibly but probably not hacking) made it impossible to add new users to the Mediawiki version. Several attempts to rectify this issue failed.
2) Mediawiki requires an SQL database underneath it. This means extra software, but worse it implies that backup is a two part process. First the data from the database must be exported and saved, then the wiki files and images. A failure to keep these aligned will created problems.
3) Dokuwiki is very easily backed up by simply copying the relevant directory and its files. As a compressed “tarball” this is a compact and dated version that can simply be unpacked on a new system.
4) Various projects I am associated with, especially the R Project for Statistical Computing with 2 million users http://www.r-project.org use Dokuwiki.
John Nash — John C Nash 2012/07/23 20:28