When you publish and promote an application, it is fair game. That Campfire (which we use and pay for) is so easily reproduced as a side project is a problem 37Signals has, not a problem for other teams.
I played with HuddleChat and the interface similarities are apparent; however, HuddleChat is not a class-for-class, id-for-id knockoff of Campfire.
Add to that the fact that most of the design of Campfire is obvious; the only distinctly 37Signals-ish aspect of it is minimalism. If you (fairly) started a project with the goal of being "at least as functional as Campfire", it's easy to see why you'd end up with something that looked similar.
When you publish and promote an application, it is fair game. That Campfire (which we use and pay for) is so easily reproduced as a side project is a problem 37Signals has, not a problem for other teams.
I played with HuddleChat and the interface similarities are apparent; however, HuddleChat is not a class-for-class, id-for-id knockoff of Campfire.
Add to that the fact that most of the design of Campfire is obvious; the only distinctly 37Signals-ish aspect of it is minimalism. If you (fairly) started a project with the goal of being "at least as functional as Campfire", it's easy to see why you'd end up with something that looked similar.