Sentimental Marginal retrieves text documents from the Productive Margin archive and submits them line by line to a sentiment analysis engine. Sentimental analysis engines can, with very broad brush-strokes, work out the emotional charge in a statement. They do so with varying results. A sentence such as "I love you but I hate war" should in theory rate positively very highly, these engines are meant to be sophisticated enough to understand the direction of our hatred is against something bad in a case such as this. A statement such as "I realy love to hate all people" would score very negatively.
Due to being a computer program Sentimental Marginal is very binary in his nature. He reacts very well to positive sentences, but his mood will blacken very quickly with a negative statement. To much negativity in a too shorter time will make him erupt into a violent rage. When Sentimental finishes reading the document he reviews how many positive statements the are as opposed to negative and then passes comment on how the paper makes him feel.