What are /r/CollaborationSoftware's favorite Products & Services?

From 3.5 billion Reddit comments

Collaboration is “the situation of two or more people working together to create or achieve the same thing”.

Although this may sound a bit generic and straightforward, this definition doesn’t limit collaboration to a specific setting or group of people and in practice the scope of collaboration in business encompasses both internal and external activities. While these both involve collaboration, they differ from each other in terms of the different parties involved, strategies and tactics deployed and of course the tools used to facilitate the collaboration process.