The part of the URL is the address of any valid feed, for instance, an http file. As with current web browsers, http: is the default protocol: feed://example.org/rss.xml Other protocols can be used, like network shared resources or local filesystem files. Use their corresponding syntax to form a valid feed: URI: feed:file:///c|/my%20documents/news.xml (this is a Windows file) feed://ftp://user:password@ftp.host.com/path/index.xml (FTP file transfer protocol) feed://file://\\server\share\index.xml (a Windows networked file) gtalk Start a chat with a Google Talk user Google Talk gtalk:chat?jid=example@gmail.com See Google Talk, XMPP, and http://juberti.blogspot.com/2006/11/gtalk-uri.html for more information irc Connecting to an Internet Relay Chat server to join a channel. IETF Draft Old IETF Draft irc://[:]/[[?]] Assuming the client knows a server associated with the name, "host" may optionally be an IRC network name. itms Used for connecting to the iTunes Music Store Apple Inc itms: lastfm Connecting to a radio stream from Last.fm. Last.fm lastfm:// or lastfm://globaltags/ or mms Windows streaming media mms://:/ Used by Windows Media Player to stream audio and/or video. msnim Adding a contact, or starting a conversation in Windows Live Messenger Windows Live Messenger Add a contact to the buddy list msnim:add?contact=nada@nowhere.com Start a conversation with a contact msnim:chat?contact=nada@nowhere.com Start a voice conversation with a contact msnim:voice?contact=nada@nowhere.com Start a video conversation with a contact msnim:video?contact=nada@nowhere.com Can be invoked from a web page or via a run command or an ie browser URL (won't work with firefox 2.0.0.8). For web pages use this HTML: Click to chat! sgn Social Graph Node Mapper Google example: sgn://social-network.example.com/?ident=bob Official documentation from sgnodemapper project. skype Launching Skype call (unofficial; see also callto:) Skype skype:[?[add|call|chat|sendfile|userinfo]] Official documentation from Skype website. view-source Shows a web page as code 'in the raw'. Mozilla, Google Chrome view-source: example: view-source:http://en.wikipedia.org/wiki/URI_scheme See view-source for details. webcal Subscribing to calendars in iCalendar format iCalendar webcal:// example: webcal://example.com/calendar.ics HTTP as a transport protocol is assumed. See Webcal for details. ymsgr Sending an instant message to a Yahoo! Contact. Yahoo! Messenger ymsgr: