Linux Softwares to Instant Messaging

QuteCom, formerly WengoPhone, was a free and open-source VoIP client supporting the SIP protocol. It enabled users to make voice and video calls, send instant messages, and connect with contacts across various networks, including Google Talk.

Blink is a robust, real-time communications client leveraging the SIP protocol for secure and private instant messaging, voice, and video calls. It emphasizes features like end-to-end encryption, file sharing, and screen sharing across various platforms.

Spark is a free, open-source instant messaging client optimized for businesses and organizations. It integrates seamlessly with Openfire servers and supports a wide range of features including group chat, file transfers, and screen sharing, making it a versatile communication tool.