Adium - Download

• Open Source, so everyone can see how Adium works and help improve it. It uses the Cocoa API, is released under the GNU GPL and is developed by Adium contributors.
• Support for a wide range of different Instant Messaging services (see the full list). Based on the libpurple protocol library.
• A delightful UI with Tabbed chat windows and Themeable WebKit Message View chat windows.
• Direct integration with your macOS Contacts App
• Combined Contacts: Merge your contacts so that each one represents a person, not an account
• A sophisticated events system including support for visual notifications via Growl and macOS's Notification Center
• OTR Encryption
• File Transfer
• Xtras and many, many other customization options
• Translations: Adium speaks 27 different languages

Note: Adium does not host any IM services, rather it is a third-party client for connecting to IM services run by others.