You can see the most recent result of efforts in this 30 second YouTube video. It demonstrates where we are with a browser plugin to add 'Like' and 'Dislike' to every tweet viewed on Twitter.com: http://www.youtube.com/watch?v=QlZVBCSXsK8
Would love to hear your thoughts on it.
The more underlying sentiment "gathering and storing" system can be found at: http://upprdwnr.com