37 signals is best known for Basecamp, a piece of immensely popular project management software. They also make Campfire which is team chat software, and Highri

37 signals is best known for Basecamp, a piece of immensely popular project management software. They also make Campfire which is team chat software, and Highrise, a CRM system for small companies. All of these products have been extremely successful. They've also written a couple of books on their approach to work. About open source: 37 signals' products is not open source. But David Hansson, one of the co-founders, built the Ruby on Rails framework, which is. They really aren't all-talk, no-walk kind of guys.