Explanation:
First of all, you might want to take a look at this:
Windows live messenger 9.0 | Webmasterunit.com
New features:
* Use of the messenger in multiple locations, to four at once.
* Signature Sounds
* Geluidje at each contact
* Spam report them
* Support for animated avatars in. Poison format
* Clickable link in the MSN contacts list
* API support (allows for easier plugins, widgets, to make ...)
* Clickable links in texts
* Ability to chat with other networks (Google Talk, AIM and ICQ)
* Multi video / audio chat (Can also in version 10, depending on the number of work)
* Vista Sidebar
* Status for PC-server (via IM PC info / warnings from a server)
Improvements
* Changes behind the scenes - Architectural changes that alter how things work, but not how things look.
* Changes logging, connectivity, presence, sending text messages, voice and video features.
* Windows Live Contacts Server - wlcomm.exe runs in the background for your contact information to keep updated and this also ensures that you are logged on you faster messenger.