+1
Mono was another de iscaza project, the Mexican guy that tried to get a job at Microsoft for 15 years by trying to impress them, it didn't work out, he left Gnome, he turned his back on open source because he was completely disillusioned of not landing a job at Microsoft, and he now works for Apple...
Mono was never a big hit, so why would .NET be a big hit.
The truth is that linux is much bigger than MS-Windows. MS-Windows may be the most used operating system on x86 PC's and small servers, but that's all it is, and the world of computing is much much bigger than that. Fact is that the field of application for MS-Windows is getting smaller all the time, and that the framework of computing in all markets is changing, and isn't taking MS-Windows into account.
Microsoft is also not a stranger to linux. Microsoft is the largest third party vendor of commercial linux solutions in the world (they sell SLES), and Microsoft uses Linux for major parts of their operation (the entire Skype network runs on linux, Microsoft Azure, etc, etc).
Microsoft knows that they have to move towards open source, for different reasons:
1. Open source development is much more powerful than closed source development, in that it can harness more resources for less money. Closed source development is very expensive, and moves really slow. Microsoft has already fired most of it's MS-Windows developers, and has already fired all of it's security developers. Those have not been replaced. Microsoft is operating MS-Windows right now on a skeleton crew, it's obvious that they have to look forward to what Windows should be after Windows X.
2. What can Microsoft really bring to the table? Is it the great code... hell no... is it the great company aura and customer friendliness... hell no... so what is it... well, they make products that non-IT-minded people want to work with and they make great marketing. The forte of Microsoft is not the development any more, it's just the bringing to market part that makes them strong. They are a software marketing company with cloud support. Maybe they realized that they could just do the same thing Google is doing: you take open source software that runs on linux, put a proprietary GUI shell on it, offer cloud support for it, and bang you've got an instant hit. Apple open sources quite a few things, it has always done that, yet they keep their products (albeit based on open source code originally) proprietary and closed source to the extent of the GUI and the user experience. Microsoft may be shooting for that Google+Apple value, which isn't a bad idea.
3. A lot of countries are banning MS-WIndows for government and educational use. In Germany, we've been able to bring the fight to Microsoft, and the government is deliberating whether or not to ban closed source operating systems. Microsoft obviously spends obscene amounts of money to lobbyists and can run it's own travel agency for fancy travel arrangements in which they wine and dine politicians and civil servants, but they have hit the point where it gets really expensive without real results. In the end, Microsoft knows that it will have to come clean on their source code.
4. Major contracts about software, like crime prevention software, tactical software, etc... are only developed for Linux for the moment. In Germany, there is a hugely successful crime prevention program that only runs on Linux, and that everybody wants, well... not everybody, because it puts a lot of responsibility onto the shoulders of law enforcement, because if they fail to follow up on the predictions of the software, they obviously fail at their job, and they'd rather have their results foggy and indeterminable. For instance, there is a police force in Germany that has been on Linux for more than 10 years now, and they have stated that they want to go back to MS-Windows, and hold on to your seats, because this is the only reason they've given: they have to watch a lot of surveillance videos, and because they have no root rights as individual users, they can't install the necessary codecs immediately, but have to request that they be installed, and that takes too much time. The real reason is that Bavaria for instance has now implemented the crime prediction software everywhere, and that they're going for it, but that takes a lot of work and responsibility, and in the Berlin region, the police would rather not have to handle that, and would rather watch YouTube movies all day. I'm exaggerating this a bit, but the general thought is exactly that. Anyway, big contract (big bucks) governmental software applications right now exist ONLY for Linux. Microsoft definitely wants in on that action, because it's very lucrative. In order to do that, they need the tools. In order to be able to hop along where the train has already left the station ten years ago without them, they need to make tools open source, so that they can connect to the dominant ecosystem they want in on, and that's Linux.
5. Microsoft and their applications partners want to develop even closed source software on the cheap. They don't want to continue developing in the US, they want to develop where it's cheaper and where there are more skilled developers around, that means China and India. Problem is, that China has quite a large operation going on to move against Microsoft for the moment. Several razzias were held in Microsoft settlements in China, PC and servers were impounded, and earlier on Microsoft products in general were prohibited for use in Governmental and educational networks. China is also the largest market in the world, and Microsoft just can't afford to lose China. The only way to fend off the Chinese authorities, is to go open source, not entirely, but just enough so that the Chinese are happy with it, pretty much in exactly the same way Apple does it. They've learned from Google that customer data trade might just not be the ultimate business plan, as Google is pretty much dead in the water in China, but if Microsoft splits up the way they treat data in the US and the rest of the world (like Google is trying to do right now by building the huge data center in the Netherlands), they can continue to sell US customer data, and more importantly keep their Patriot Act obligations intact and continue to get fat contracts from the US government, and at the same time provide more data protection in the rest of the world, complying with human rights and consumer rights there, and still stay in business. This might actually work, because Microsoft already has the data centers needed for exactly that. IBM has figured this out 25 years ago, and they implemented it, but soon they were too early to the party, and instead of conquering a larger market, they actually had to slow down because of the impact of the intelligence community on the whole thing (like an IBM director being found murdered in his Volvo in France under suspicious circumstances, very Olson-like, for those that remember that).