The not-so-secret sauce of DokuWiki's flexibility is plugins: if a feature you need is missing from the list of default DokuWiki functionality, chances are there is a plugin that fills the gap. And if the ability to work on your DokuWiki files offline is high on your wish list, you will be pleased to learn that Andreas Gohr, the lead developer of DokuWiki, has written the Sync plugin that allows you to do just that. As the name suggests, the plugin lets you sync two or several DokuWiki installations. This way, you can edit the pages of the DokuWiki installation running on your machine and then push the changes to DokuWiki on your Web site. The plugin also allows you to restrict syncing to specific namespaces, and you can choose whether you want to sync pages, media files, or both. In addition to that, the plugin can detect changes on both ends and suggest you a sync direction. After taking the Sync plugin for a spin, I can attest that it's pretty straightforward in use and works like a charm.

Now you might wonder why I haven't provided the download link. The reason is simple: there is no one. Instead of releasing the plugin to the public, Andreas Gohr has decided to sell it, but in a rather unusual manner. If you like the plugin, you can donate any amount you like or can afford. Once donations reach the $750 limit, the developer will release the plugin under the GPLv2 license (you can see a more detailed description of the experiment on the developer's blog). If you want to see what other users have to say about this, check the following thread at DokuWiki's mailing list. For the record: I've already donated a few bucks and hope that the experiment will succeed.