Microsoft has recently announced that they are moving .Net to open source and supporting Mac and Linux in addition to their Windows OS with Visual Studio Community 2013. Also, Visual Studio 2015 will support iOS and Android development.
Frankly, it's a little confusing because in some places MS mentions Mac and Linux, but very few, and they mention iOS and Android in lots of places, but not everywhere. So the support may be different than what I said.
Nevertheless, MS is opening up. Or at least seeming to.
Their timing couldn't be better, in my opinion.
Oracle is working hard to poison Java. I'm not entirely sure why, unless they think that ticking off any Java programmers and users outside those developing middleware for Oracle's products is a really great strategy. Their support for Java as a general programming language, as Sun did, has been piss-poor since day 1. Every so often they make a grand gesture to try to present themselves as interested, but the product they offer now is not something I could send someone out to install with a good conscience. What kind of an honest, large-scale company thinks that half-sneaking some crap software in under the cover of installing their own is a really great idea? Not one that really treasures the individual customers, I can tell you (and yes, Adobe is on this particular excrement list, too.)
Couple that with their poor responsiveness to security concerns, to the point where the Java language is treated as a sort of worm or virus by most software, and you've got a company that's decided to leave a hole in the cross-platform development market simply because their interests are elsewhere.
Cross Platform Alternatives
C# is Microsoft's outgrowth from their own attempt at embrace, extend, exterminate targeting Java. It's a very good language, including the good parts of Java while having a set of libraries (.Net) that don't have the Java API's less than useless historical cruft but do have everything good about the API, which made Microsoft look really cool to programmers when it came out as most were not familiar with the Java API itself.
Switching to C# from Java is an afternoon's exercise. But it and the .Net library started out wed to the Microsoft platform.
Enter Mono, a cross-platform implementation of .Net supporting the C# language based on Microsoft's ECMA standard for its products. It has been growing, at least in part on the back of the decline of Java, as well as bringing the good things about C# and .Net to Mac and Linux development. It doesn't hurt that it is the core that drives products like the Unity cross-platform game-development system, too.
Now Microsoft is combining their products with Mono, and extending their reach to Android and iOS.
There are a Couple of Ways This Could Go (and Possibly More)
In Future A, Microsoft does the excellent work they do in producing development tools, but now with a return to platform-agnosticism. This encourages programmers to develop for Windows and Windows Phone as well, since programmers who might otherwise have been targetting only iOS or Android will be selecting these tools for their intrinsic value as development tools to write programs for their favored OS, then decide to toss a Windows/WinPho version out there, too, since it's not costing them any significant extra effort and might end up fattening the coffers a bit.
Microsoft gains developers for its platforms, draws "thought leader" and technical leaders into their ecosystem, and the developers get the advantage of having good development tools for any major platform they choose.
In Future B, Microsoft uses this as a ploy to draw programmers in, but cross-platform support is sloppy, or delivered slowly, or lags behind the native capabilities of the non-MS platforms. Perhaps it doesn't play well with the various different versions of Android, or maybe the Mac and Linux native code suffers by comparison with code developed with native tools for those platforms.
It turns out to just be hype. Maybe there are forces within MS that fight the release of solid tools that are truly cross-platform, so they ensure that foreign platform support is sub-par, thinking that they're helping their own products by making it "harder" to develop for other platforms. The only point of cross-platform, to them, is to allow Windows patriots to proclaim themselves cross-platform developers without knowing anything about the competition.
In this future, Windows does not become the programmer's platform of choice, Windows has extra costs of development that make it less attractive as a development target when another platform is the one that's going to pay the bills (probably iOS), and life goes on as it does today with possibly the Microsoft touch putting some poison into Mono.
I can only hope that the upper management at MS is committed to Future A. because that's what it's going to take to keep Future B from stepping in any time it pleases.
Microsoft, Doing You Know What in Their Own Messkit for the Past Decade
Windows 7 was a boon for programmers when it came out. I and many other programmers I know had been feeling somewhat kicked about by Apple, didn't see tools with the same level of sophistication on Linux (and generally more system maintenance than the commercial OSes, and system maintenance doesn't pay bills), and Windows 7 was a viable place to go, or to at least have as a second OS on our desk for conducting development and testing.
Windows 8 added some nice stuff behind the scenes, but not without wrecking the usability of the platform, as well as making it a far less attractive target for development. In my case, I abandoned Windows as a target for native development about a decade ago, and was waiting on Windows 8 to see if I might add it to my repertoire again. The answer became "no". Windows 10 will determine whether I ever consider it a serious platform for anything at all in the future, as the professional applications that I currently use on Windows have all become multi-platform over the past several years, so I can move my licenses over to Mac OS or Linux for all of them.
If Microsoft gets it right with their development tools, and Windows 10 restores the power to the desktop that earlier versions provided--not just a false appearance of it as in Windows 8.1--then they stand to become the defacto professional desktop again.
And given that the consumer desktop is the market that is dying in the face of mobile platforms, one would hope that they are bright enough to strategically commit to a powerful professional computer OS again. While the mass market computer is probably going away, there was a profitable professional/hobbyist market before the internet boom put a computer in practically every household. That professional market stands to be even larger than the historical one, as many professions that had nothing to do with computers now rely on them, and many new professions have arisen over the past 25 years that rely on the computer.
Also, there's a possibility that the mobile device as a computer replacement is just a flash in the pan. Most people bought their mobile devices in place of a routine upgrade to their home computer for one cycle. Now that they have tablets, the tablet market is going flat while computers are seeing a modest rise in sales. I think just about everyone has had a chance to discover that the touch interface is very limited in what it can do with current technology. It's severely error-prone and it's not well suited to complex activities. It's too soon to read now, but there's a chance the tablet may be relegated to specialty use status, with the keyboard-equipped computer regaining its status as the "real" computer behind the smartphone's limited purposes as a personal communication and light entertainment device. We'll see.
The phone isn't going to go away, though. It's going to be the most personal of personal computers, at least until it's replaced by a small tablet and a complete phone the size of an earpiece, or some other revolutionary turn that gets people to give up a screen for convenience. So supporting the mobile platforms is, for Microsoft, probably a must to their survival. At least until they can get real market share for Winpho.
Either way, if Microsoft plays their cards right, going to platform-agnosticism in their development tools could be a really good thing for everybody--including and especially Microsoft.