正式宣布：终止运营！

Core Viewpoint - Microsoft announced the closure of Skype, a service that has been operational for 21 years, to focus on the development of new features for Microsoft Teams, including AI tools [1][8]. Group 1: Closure of Skype - Microsoft is shutting down Skype to concentrate resources on enhancing Microsoft Teams [8]. - The transition will allow users to log into Teams using their Skype accounts, with automatic migration of contacts and chat history [8]. Group 2: Historical Context - Skype was founded in 2003 and gained popularity for offering free online calls during a time when international calls were expensive, reaching 11 million registered users by 2004 [10]. - By 2008, Skype's user base exceeded 405 million, but its acquisition by eBay in 2005 did not yield the expected success, leading to its sale in 2009 [10]. - Microsoft acquired Skype in 2011, but the rise of mobile internet and competing platforms like WhatsApp and WeChat significantly impacted Skype's user engagement [10][11]. Group 3: User Engagement Decline - Skype's monthly active users peaked at over 300 million in 2016, but by 2023, daily active users had dwindled to 36 million [11]. - The shift towards mobile and cloud communication has fundamentally altered the industry, contributing to Skype's decline [11].