What are some alternatives?
When comparing Adium and Miranda IM, you can also consider the following products
Pidgin - Pidgin is an easy to use and free chat client used by millions. Connect to AIM, MSN, Yahoo, and more chat networks all at once.
Trillian - Trillian is a decentralized and federated instant messaging platform that lets your whole company send private and group messages, keep tabs on what co-workers are doing, share files, and much more.
Skype - Stay in touch with your family and friends for free on Skype. Download Skype today to chat and call on desktop and mobile.
Jitsi - Open-source video calling and chat platform.
Facebook Messenger - Facebook Messenger is a faster way to message.
Empathy - Apps/Empathy - GNOME Wiki!