RetroShare is open source software for encrypted filesharing, serverless email, instant messaging, online chat, and BBS, based on a friend-to-friend network built on GNU Privacy Guard (GPG). Developed by DrBob
License: Open Source
RetroShare offers a decentralized and secure communication platform focused on privacy, while Windows Live Messenger was a user-friendly instant messaging service integrated with Microsoft products but has been discontinued. The choice between them depends on the need for privacy and security versus ease of use and integration with other services.