+
+StartUserXRDS: Start XRDS output (right after the opening XRDS tag)
+- $action: the current action
+- &$xrdsoutputter - XRDSOutputter object to write to
+
+EndUserXRDS: End XRDS output (right before the closing XRDS tag)
+- $action: the current action
+- &$xrdsoutputter - XRDSOutputter object to write to
+
+StartPublicXRDS: Start XRDS output (right after the opening XRDS tag)
+- $action: the current action
+- &$xrdsoutputter - XRDSOutputter object to write to
+
+EndPublicXRDS: End XRDS output (right before the closing XRDS tag)
+- $action: the current action
+- &$xrdsoutputter - XRDSOutputter object to write to
+
+StartCheckPassword: Check a username/password
+- $nickname: The nickname to check
+- $password: The password to check
+- &$authenticatedUser: set to User object if credentials match a user.
+
+EndCheckPassword: After checking a username/password pair
+- $nickname: The nickname that was checked
+- $password: The password that was checked
+- $authenticatedUser: User object if credentials match a user, else null.
+
+StartChangePassword: Before changing a password
+- $user: user
+- $oldpassword: the user's old password
+- $newpassword: the desired new password
+
+EndChangePassword: After changing a password
+- $user: user
+
+UserDeleteRelated: Specify additional tables to delete entries from when deleting users
+- $user: User object
+- &$related: array of DB_DataObject class names to delete entries on matching user_id.
+
+GetUrlShorteners: Specify URL shorteners that are available for use
+- &$shorteners: append your shortener to this array like so: $shorteners[shortenerName]=array('display'=>display, 'freeService'=>boolean)
+
+StartShortenUrl: About to shorten a URL
+- $url: url to be shortened
+- $shortenerName: name of the requested shortener
+- &$shortenedUrl: short version of the url
+
+EndShortenUrl: After a URL has been shortened
+- $url: url to be shortened
+- $shortenerName: name of the requested shortener
+- $shortenedUrl: short version of the url
+