Twitter-unread-notifier is a project mainly written in JavaScript, it's free.
A Fluid.app Userscript for twitter.com
A userscript for Fluid.app and twitter.com
This userscript can be used with your twitter.com instance of Fluid.app (SSB) to update the dock badge with the count of unread tweets. It also displays a growl notification with the unread count every 10 minutes, just in case you don't watch your dock.
This also now functions correctly with #newtwitter.
~/Library/Application Support/Fluid/SSB/<your-ssb-name>/Userscripts
. You can also access this from your Twitter SSB using Userscripts > Open Userscripts Folder
.Userscripts > Reload All Userscripts
, and then Userscripts > Twitter Unread Notifier
.And that's it! You may need to reload the page or restart your SSB to ensure it has been installed correctly.