Briefly: WebDAV stands for “Web-based Distributed Authoring and Versioning”. It is a set of extensions to the HTTP protocol which allows users to collaboratively edit and manage files on remote web servers.
DAV allows users to remotely share files and allows them to write to them.HTTP gave them read access, while DAV gives them write access.
DAV is a protocol. More specifically, it is an extension of the HTTP/1.1 protocol. DAV adds new HTTP methods and headers. In addition, DAV specifies how to use the new extensions, how to format request and response bodies, how existing HTTP behavior may change, etc.
DAV is a possible replacement to FTP and CVS.
WebDAV uses port 80, the same port used by HTTP for web access. So using WebDAV means you don’t have to open any extra ports on your firewall.
WebDAV lets only one user modify a file at a time, while allowing multiple users to read it. This allows files to be locked while they are being edited, preventing unexpected changes from occurring.
WebDAV lets you edit files on the server instead of needing to download them first to the client. Editing files remotely using WebDAV is as easy as if they were locally present, and the whole process is transparent to the content producer.
For full details visit