The Rails/Murb drama a few years ago is another good example I think. A bunch of people decided they didn’t like the directions Rails was going in, created a co

The Rails/Murb drama a few years ago is another good example I think. A bunch of people decided they didn’t like the directions Rails was going in, created a competing framework, and after proving the concept was sound ended up introducing a lot of the unique features back into what became Rails 3.