YMulti Messenger (formerly Y! Multi Messenger)

Just like its name suggests, Y! Multi Messenger is an application that allows users to run multiple instances of Yahoo! Messenger (YM), and thus chat online using more than a single ID, making it suitable for both personal and professional use.

Lightweight and easy to use

Y! Multi Messenger consists of a tiny executable whose setup takes only a few seconds. Also, the interface is nothing more than a simple screen that enables you to activate or disable the patch which allows the running of multiple YM instances.
This tool is designed to patch Yahoo! Messenger version 8 and above and in order to be able to allow it to work its magic, the YM application should be closed. Please note that this is a one-time operation because as soon as the patch is activated you will no longer need to run the app again.

Return to the initial state with a single click

The 'Disable Multi' button will revert any changes made by the application and you will no longer be able to run several instances of Yahoo! Messenger, as it will come back to its initial state. This comes in handy as a security measure in case unexpected situations occur.

In conclusion

That's basically the whole story with Y! Multi Messenger; it is but a simple program with a plain interface that does a simple yet so useful thing. All in all, this software is definitely a must have for all those who need to stay online with more than a single Yahoo! Messenger ID.