This app learned by looking at tweets of twitter users that followed well none left or right wing platforms. It then tried, using a bayes classifier, to classify twitter users based on their recent tweets (your outcome could change after tweeting). If you type in a user handle it will look for these words and try to make a prediction. This classifier is not perfect, it has a 87% success rate with the dataset it learned on. There is no database holding the political affiliation of each twitter user.