Slack came to life three years ago, out of a failed video game, and, as messaging software, combines rich data on how people use a product with information on how people feel about using it. When it debuted in 2014, word of mouth catapulted Slack to a value of $4 billion. Now, the private company has attracted competition from Microsoft, which last fall unveiled Teams, free to 85 million users of Office 365, and Facebook with its free collaboration tool Workplace. A smaller company, Atlassian, has also had success. Continue reading Slack Faces Off Against Bigger Competitors, Tweaks Software