The…
Windows Mobile Live Messenger Web Client
…is takes Live Messenger (formerly MSN Messenger) out of the mobile client world and into the mobile web client world. The overall experience is not too bad. I still prefer having a Mobile Live Messenger client but recognize that having a web version allows for more frequent updates and, hopefully, more iterative innovation.
These mobile web client experiments by Microsoft and others will probably most benefit, um, Apple, Inc. What? You ask? Why?
After the initial afterglow and reality distortion field diminished as MacWorld 2007 receded from reality to memory, Apple took a lot of heat in the press because their initial stand is that they will not permit applications to be installed on the Apple iPhone by the end user. However, the iPhone reportedly has a full Safari browser. If this is true, this means the iPhone should be capable of fully participating in Web 2.0-ish activities in a way that current web-enabled phones cannot. So, applications could be delivered or redeployed as web apps like Windows Mobile Live Messenger Web Client. Assuming you are always connected either by EDGE (phone data) or WiFi (wireless broadband), you would always have access to web-enabled applications.