Dokuwiki is a wiki implementation that uses plain text files to store data, rather than a database management system.
The most important benefit this provides, is that the entire wiki is easily duplicated and distributed.
One example of where this would be an advantage: an organisation that, for security reasons, does not wish laptop users to access the Web from outside the company firewall but does require that those users have access to the company's knowledge base. Because the entire wiki can be copied as a single entity, it is easy to arrange for the laptops to be updated with the wiki when they are connected to the organisation's infrastructure.
There is a thriving Dokuwiki community, which provides additional modules for the project including a wide variety of layout templates.
Dokuwiki is only partially compatible with pages from Mediawiki sites, as most of the formatting conventions are different. However, the formats are sufficiently similar that page source can easily be converted with, for example, a short Perl script.
If you get the message:
Forbidden You don't have permission to access /install.php on this server.
when you try to run the installer, you may have one of the following problems: