Recently, however, I introduced it at work as a way of encouraging the team I manage to work collaboratively. We have a fortnightly catch up where we talk through solutions, pick new problems (we have a script that randomly picks an easy, medium and hard problem, which has become an exciting ritual), and then we have an initial discussion about each of the new problems.
It's a good way to foster group work. It's also a great way to introduce people to using version control and pull-requests in a non-scary way!