As some clever users have already discovered, the Gmail Notifier for Mac OS X we launched last week can do a little bit more than meets the eye. A couple interesting features:

1. Fetch mail for only one Gmail Label
This is very useful if you only want to be "notified" about certain emails. For example, to only fetch mail with the label "ImportantStuff", run the following command from the Terminal:

defaults write Label -string "ImportantStuff"

2. Extend the Notifier using plugins
The Gmail Notifier supports plugins written in AppleScript, or full-blown Cocoa Bundles in Objective-C. Details about the Objective-C plugin API can be found inside the Gmail Notifier application bundle in the required header file, GGPluginProtocol.h (control+click Gmail -> Show Package Contents -> Contents -> Headers).

AppleScript plugins are written by simply implementing a handler like:

on NewMessagesReceived(messages, fullCount)
-- Your code goes here...
end NewMessagesReceived

To install, simply copy the script (plugin) to Library/Application Support/Gmail Notifier (create the directory if it doesn't exist), and restart the Gmail Notifier. An example of a great plugin for the Gmail Notifier for MacOS X is the Gmail+Growl plugin, which sends Growl notifications when new mail arrives.

Our thanks to those of you who have already written cool plugins. We look forward to many more!