I was listening to a radio program the other day where the host and his guest were talking about how President Donald Trump’s tweets could sink or spike a company’s stock price. They said that it takes about four seconds after Trump tweets about a company to see the effect on the company’s stock price. That got me thinking: what if we could listen for specific tweets from specific users or specific topics and recipients, and then act on the detected tweet depending on whether it has positive or negative sentiment. For example, if President Trump tweets congratulations to a company for adding jobs in the U.S., the tweet listener can send a buy signal to an automated stock trading system for that company’s stock. Conversely, a negative tweet will generate a sell signal for a stock before the price takes a dive.