Use a tabbed web browser? Even if you don't, you might find tabbed conversations useful for organizing your chats by converting a myriad of windows into a simple single one. Vertical tabs on the left, normal tabs on the top. You name it. You can also use tabs to group just some special chats and keep all the rest in normal windows if you want.
Quick Texts
Quick Texts

Tired of always typing the same? Meet quick texts and text replacements: automatic and customizable messages that can be sent with a simple shortcut or typed command, or automatic text replacing to use written shortcuts or using it as a word filter.
Custom Sounds
Custom Sounds

The Custom Emotion Sound feature brings sound integration in Messenger to the next level by allowing users to send their own sounds during a conversation. Sounds are played instantly on both ends and are transferred automatically and transparently when needed.

New emotion sounds can be easily created from existing sound files (such as MP3s) or can be recorded live from a microphone or other audio source but, if sound authoring isn't your thing, thousands of sounds can be found in the public database or imported from sound packs.
Colors, formatting and commands
Colors, formatting and commands

Messenger Plus! gives you the possibility to choose any color you want for front and background, and add formatting, such as bold, italic, underlined and stoke-out. It also lets you control almost every aspect of Messenger via text shortcuts called commands, much like the ones in traditional IRC chat rooms.
Recharge your Messenger: Various additions to manage your contacts and conversations
Personalized Status
Personalized Status

Create custom away or busy statuses with a special name tag, personal message or even an auto-responder. Set a timer to reset your status in a certain time and organize presets to reuse common statuses.
Messenger Lock
Messenger Lock

Be it for security in shared computer environments or for avoiding your boss (which would be wrong wrong wrong!), this feature lets you lock Messenger with a simple shorcut (or Plus! menu command) and hide it in the system tray with an inconspicuous icon, the ability to password protect it and to automatically send a message to your contacts to inform them when you have locked and unlocked your Messenger.
Contacts on Desktop
Contacts on Desktop

Similar to what ICQ used to offer, you can show the status of any desired contact on your desktop in the form of small floating windows. You can drag and drop messages or links into these to send a message to the contact, or drop a file to start a transfer.
HTML Chat Logging
HTML Chat Logging

Messenger Plus! Live lets you keep logs of all your conversations in a much more flexible way than the original Messenger ones. Heck, Plus! let you do that for years before MSN Messenger added it as a standard, though not perfect, feature. But what does Plus! Live improve over it?

* HTML Logs: beautiful styling and the flexibility of files you can take anywhere
* Emoticons and Winks: Everything is logged, even custom emoticons are kept and winks shown as thumbnails
* Log viewer: Shows you all your logs sorted by contact and date within Messenger Plus!
* Skinnable logs: if you get tired of the default style of logs and know CSS or get a custom.css file, just drop it in your logs folder and change their look!

Events
Event viewer and event logging

Contact sign ins and sign outs, status changes, display name and personal messages changes. Everything can be logged and archived in XML-based files which you can view from your browser.

You can also use the Event Viewer in the Plus! menu to view this info in real time, to find if a certain contact signed in earlier or analyze their status changing behaviour, or even their musical tastes!
Contact List Clean-up
Contact List Clean-up

Easily view stats about all your contacts (last sign in, when you had the last conversation, etc.) and clean your contact list deleting old and repeated contacts.
Polygamy
Polygamy (run multiple Messenger sessions)

Just check a box in the Messenger Plus! Live Preferences and you'll be up and running for logging into more than one Messenger session at the same time, all integrating with Plus! correctly and without patching any files.
Plus endless extensibility with the ******ing Architecture

Messenger Plus! Live provides its own ******ing environment to developers who want to add their own features to Windows Live Messenger. You can get ******s or learn how to develop your own from the ******s section.

For those of you who are a mere mortal incapable of creating a ******: ******s mean new ideas, new features and more fun in Messenger, again and again, brought to you by other developers from the Messenger community!
And it's all free.

Messenger Plus! is freeware and you are encouraged to send it to your friends. You'll never have to pay a dime to benefit from all the features of the program. Messenger Plus! does not contain any kind of spyware or trojan. The embedded optional sponsor is adware and you get a clear choice to install it or not during setup, risk free! For those who want to support the development but prefer not to install the sponsor program, you are encouraged to visit the online store, or give the developer a minute of your time by sending a postcard.