This post was published 4 years 2 months 18 days ago. Therefore, it may well be out of date. Do not reply on the contents of this post being accurate. For Mac OS X, Adium allows users to use one instant messaging (IM) client application to connect to multiple IM services.
For Windows, Linux, BSD, and other UNIX platforms, Pidgin offers the same.
They allow you to connect to AOL Instant Messenger, MSN Messenger, Yahoo Messenger, .Mac/Apple Chat, GoogleTalk, Lotus SameTime, MySpaceIM, and many more. Both can be complemented with the Skype API Plugin.
Pros
- All buddies/contacts are in one place
- Use only one application to communication cross-IM
- Open source
Cons
- Currently no video or voice chat as you can with Apple Chat or Skype
- Skype must be running if you want to use Adium/Pidgin to IM with Skype accounts (although there is an option to hide Skype so that only the Adium/Pidgin window is in use)
- You must have an account with each service provider to communication x-IM, i.e. you can’t use your GTalk account to IM with Skype users.