The real story with the Exchange hack is that Microsoft created a backdoor for NSA that was exploited by hackers for all over the world. This once again demonstrates the value of using open source software that can be independently audited. https://www.tweaktown.com/news/57538/microsoft-gives-nsa-backdoor-complains-exploits/index.html
@yogthos totally agree, but still its possible to push backdoors into open source and free software projects. It's pretty hard to audit over 1 million lines of code project. I would say the code should be accessible for everyone and codebase should be auditable (not bloated) by anyone. We can see the rise of bloat everywhere and often even accessible source code have a chance to be not read and fully understood by maintainers.
Server run by the main developers of the project It is not focused on any particular niche interest - everyone is welcome as long as you follow our code of conduct!