Trillian
Freemium
Trillian is a proprietary multiprotocol instant messaging application.
IM+
Freemium
IM+ supports simultaneously major IM services, including Google Talk, Twitter DMs, Yahoo!, AIM/iChat, ICQ, Jabber (and Slack through Jabber), etc.
Disa
Open Source
Disa is your new messaging hub. Conversations from different services can seamlessly be joined together, or disbanded within seconds.
Jitsi
Open Source
Jitsi (formerly SIP Communicator) is a free and open source multiplatform voice (VoIP), videoconferencing and instant messaging application.
KakaoTalk
Freemium
KakaoTalk (Korean: 카카오톡), or sometimes KaTalk, is a free mobile instant messaging application for smartphones with free text and free call features.
