Webdavfs serves files exported by a WebDAV-supporting Web server. It essentially translates between WebDAV messages (HTTP) and styx messages.
XBMC Blastdav is a simple WebDAV-like server for streaming content to XBMC. It works through proxies and tunnels, and even streams smoothly from a Raspberry Pi.
A backup software system.
A query processing engine that defends against inference problems.