Normally, we only can login our user name or ID in yahoo messenger with one ID, especially if you used an official yahoo messenger. But we also understand that we can use another ID with a simple step by making another public ID. With a public ID we can chat with different ID in one login user name. But, we cannot be join chat room with two or more public ID in the same time. We can only chat with two ID or more in the
same time by using Multiple ID. We can use multiple ID [MultiID] to enter the chat room with more than one ID. The maximum ID you can be entered to the chat room depending on the willing of your self and the connection of the internet you have. If the connection is too slow, it can be make your self disconnected. You can downloaded multi id for free from this link (It also include how to create multi id manually using register editor in windows:
Download YM Multi ID
MultiID can be achieved by some simple step. If you have enough experience and knowledge with your computer, especially working with register edit, you can achieve multiID by editing your yahoo messenger register in windows. Or if you want a simple way, you can download a Patch for MultiID Yahoo Messenger. Below this paragraph I am willing to share with you MultiID Yahoo Messenger.