Detecting the mood of a tweet or message
machine-learning, php
Solution
I would suggest AlchemyAPI. They have pretty simple APIs ( which shouldn't be difficult to use. For your specific case, look into here
Problem
Are there any APIs that can extract moods from a string (for use in PHP but can be implemented in any language)? If one doesn't exist, how would I go about building a classifier, presumably something related to machine learning, where I extract words with known positive/negativity.