How to make my yahoo messenger multi

Enable Hidden Secret Polygamy (Multi-Login) Feature of Yahoo! Messenger to Run Multiple Instances at Same Time

NOTE: This tutorial is very old and was posted a few years back for Yahoo! Messenger older versions but the same trick still works for newer versions. We have updated the tutorial with more detailed information along with new screenshots.

We all know that there are many patchers available for Windows Live Messenger like A-Patch which enable the secret "polygamy" feature in WLM which allows you to run multiple instances of messenger at the same time. This feature is also called "multi-login" feature by many people because you can login using different accounts in different instances of messenger.
But did you know the same polygamy feature also exists in Yahoo! Messenger? Yes, its true. This polygamy feature exists in Yahoo! Messenger since ages but surprisingly the Yahoo! team never enabled it by default or never announced it officially.
Anyway if you want to enable this secret feature in Yahoo! Messenger, you just need to follow a few simple steps given in this tutorial.
Following is a screenshot of running 2 instances of Yahoo! messenger:

Following are the required steps to enable Polygamy aka Multi-login feature in Yahoo! Messenger:
1. Type regedit in RUN or Start Menu search box and press Enter. It'll open Registry Editor.
2. Now go to following key:

HKEY_CURRENT_USER\Software\Yahoo\pager\Test

3. In right-side pane, you'll see a DWORD Plural. Its value would be set to 0. You just need to change its value to 1 to enable polygamy feature as shown in following screenshot:

4. That's it. Close Registry Editor and now you'll be able to run multiple instances of Yahoo! Messenger and now you can login using multiple Yahoo! account in multiple instances of the messenger.
PS: If you don't want to do the task manually and want a ready-made registry script to do the task automatically, just download following ZIP file, extract it and run the extracted REG file. It'll ask for confirmation, accept it:
Download Registry Script