I asked the finance guys at the asset management firm I worked at last, and they said that the #1 value to them was in the chat. So many deals are arranged via the built-in chat system. News can be acquired from many places, but if you capture the communication (or create the platform, as BB did), then you capture your audience.

It's very hard to break out of that, because doing so means you're now excluded from some of the most useful and important information. Nobody wants to be first to leave, and convincing enough users to leave en masse to create or use an alternative seems impossible at this point.