Trello is a free web-based project management application originally made by Fog Creek Software in 2011, that spun out to be its own company in 2014.It operates a freemium business model, as well as being cross-subsidized by other Fog Creek Software products. A basic service is provided free of charge, though a Business Class paid-for service was launched in 2013.In July 2012, the site surpassed 500,000 users.