Messenger Plus! Live is an add-on for Windows Live Messenger. This program adds a lot of new functions to your Messenger.
Once installed, the program will create a new option on your Windows Live toolbar. Through this option (that you can turn into an animated icon), you can access the program´s menu.
The program will record every action taken in a log that you can read using the "Event Viewer" window. The "Chat Log Viewer" will register every chat, and you can access all the information very easily.
Messenger Plus! Live can also lock the Messenger, hiding the windows and warnings that this program usually displays. It also includes options that will let you clean your contact list. It is possible to use sounds that will be played when you are chatting, and you can activate them by using a hot key.
The program can use different skins, and even includes a program to design your own skin, both for the Messenger itself and for the chat window.
If you use a webcam with Messenger, the Plus! program will let you choose different video settings for the image produced by that device.
This program also has a complete list of plug-ins that can be downloaded and installed. The list of plug-ins will let you add more features to your Windows Live! Messenger. This list grows day by day.
Considering all this, my opinion is that Messenger Plus! Live can be a useful add-on for people that want to have more control on the appearance and features of Windows Live!. But most of us will be fine without using it.