After the acquisition by Microsoft of the communication software vendor Skype, changes were made to the platform, towards are more centralized controlled system.
Pressured for questions if the company works together with intelligence agencies to allow access to user communication were not clearly answered, leading to the suspicion of the company doing so.
archived source: https://wellthissucks.xyz/2012/07/20/skype-likely-allows-3rd-party-access-to-all-conversations-archived-source/