The internet works because we have known open standards about how to do things with it. Email works because there are defined standards for it, likewise with webpages. You're not forced to use a particular program to read your mail, or view webpages, etc., that may not be available to you, or may be a completely pain to have to use, unless you come across one of the many morons in webspace who don't know what they're doing, or those arseholes in webspace who deliberately break things because of their own selfishness.
Once again, a communication protocol has been deliberately broken by a corporation (Microsoft), who believes that they should have the right to dominate the internet, and not let anyone else be involved, in a fucked-up attempt to make themselves king of the hill. It's not that other programs couldn't possibly be compatible, nor even that other programs are actually a bigger security risk than their own, they're just being asses about it.
For many years, I've used the program called “Pidgin,” as a single program that let me chat with people on ICQ, Yahoo, Jabber, Facebook, MSN, and other instant messaging protocols, in a very convenient way (one small program, that doesn't dominate my desktop), instead of very inconveniently having to run several separate programs for each different type of instant messaging protocol (many of them quite awful, and huge). But now they (Microsoft) have broken compatibility with all alternative clients, not just Pidgin, so I can't use MSN anymore.
So, for the time being, until they pull their heads out of their arses and learn how to play ball with the rest of the world, you'll have to use a different instant messaging protocol to communicate with me, and many others. Because I, sure as hell, am not going to be using their program on Windows. I don't even use Windows, I abandoned Windows for Linux, many years ago, and have not regretted it. And they don't produce a program that works on my operating system.
So, while Microsoft continues to shoot themselves in the foot, I encourage you to use something completely different for instant messaging, not just when communicating with me, but with everyone else that you know.