Sentiment detection is fast becoming a popular method of deciphering Tweets, news stories and other content on the web. TechCrunch50 startup Affective Interfaces, which launched at the Business Applications session today, has built emotion sensing technology that detects a web user's facial expressions via a webcam. Affective Interfaces's SaaS uses a webcam to monitor facial expressions such as smiles, frowns and other emotions. The software analyzes these expressions and how they related to different parts of a site. So for example, Affective Interfaces will compare the emotions of a user while they are on CNN.com vs. Gawker.com. Or the software could be aptly used to determine emotions on an e-commerce site, like Zappos.com, to see what emotions affect engagement and purchasing decisions. TechCrunch50 Conference 2009 : September 14-15, 2009, San Francisco