This tool is written in PHP and it performs Sentiment Analysis on Twitter messages by using the Datumbox API 1.0v.
To read more about how it works, how it should be configured etc check out the original blog post: http://blog.datumbox.com/how-to-build-your-own-twitter-sentiment-analysis-tool/
Download API Documentation and Code Samples: http://www.datumbox.com/machine-learning-api/
Sign-up for free API Key: http://www.datumbox.com/users/register/
View your API Key: http://www.datumbox.com/apikeys/view/
PHP Twitter API Client: https://github.com/timwhitlock/php-twitter-api