WordTarget is a Mac OS X app built with RubyMotion that sits unobtrusively in your menubar and will track your word count across applications. It helps you keep track of your word count each day so you can work towards hitting daily writing goals, letting you start and stop the tracking so you can ignore certain things, and giving you a quick and easy view into your daily history (now complete with per-application breakdown of word counts!), all from the status bar.
It's available for $5.99/£4.49 on the Mac App Store, and you can find out more details about the app here.
A few promo tokens to get it for free for anyone interested:
Any comments, questions or suggestions are more than welcome!
@ejdraper / @kickcode