Unity is a proprietary project that Mr. de Icaza is forever going on about in his blog. It is pure awesome rocks, of course. Here is a Windows screenshot:

Windows: The Mono Standard

Now, check out the Linux version and realize the true power of cross-platform development with Mono:

Linux: The Mono Alternative

Hmmm. That wasn’t as impressive as one hoped.

Just desserts

Do not worry, though, because since bringing Windows developers over to Linux is one-half of the whole point of Mono, and because the mono project is really promoting Unity, you can see the rewards when Unity is asked about Linux support:

The only decision we made so far is that “someday we will support it”. Nothing more concrete is decided yet.

Hooray! That and 30 pieces of silver will get you a Team Mono t-shirt! They have lots of nice things to say about Mono though:

Unity now enjoys a rapidly growing user base on both Windows and Mac OSX, and powers many types of game development, architecture visualization, advertising and educational solutions. “Looking back”, says Ante, “without Mono Unity wouldn’t have been possible.”

I for one am glad that Novell has torn the community apart to deliver a platform that delivers for the Windows and OSX and iPhone platforms. I think we can all agree it represents a major win for Linux; without Mono it wouldn’t have been possible.

But Microsoft technology is the best

If only there were some GPL cross-platform non-Microsoft tool that could develop 3D games and apps. I don’t expect FLOSS could deliver something like that without slavishly copying Microsoft. After all, C# and .NET represent the absolute pinnacle of technology.

We’d probably only end up with something that looked like this:

Not-mono: Not best-of-breed

Yeah, not much value in all that hippie GPL junk.

New Slogan Time

Mono: Extending Redmond’s Reach into Proprietary Platforms on the backs of “Open Source” developers since 2001. Also some Linux apps in there somewhere too.

First off, I’ve always thought this was a bogus reason. As a general rule, Windows developers don’t care anything about non-Windows platforms. Period. Windows developers are no more going to target Mono as a build environment than they will target Wine. Sure, you may find a few exceptions – I even know one nice audio project that supports Wine – but those are by far, very far, the exception.

Here’s a look at what some Windows developers and project users/enthusiasts think about Mono when push comes to shove:

umbraco:

As I mentioned in the post, we would have mono support by now if mono supported ASP.NET 100%. It doesn’t.

While mono support in theory would open up umbraco towards enterprises with *nix stacks, I doubt that they would choose anything mono related, due to mono still being experimental.

And after all we are a ASP.NET based cms. And the primary focus should be optimizing umbraco for ASP.NET. And adding official mono support, would mean that we would always be a .NET framework behind, so no LINQ, no WWF, etc. As much as I find mono support cool from a “geek perspective”, I don’t think it’s worth the drawbacks.

[Update: Umbraco's founder comments.]

DotNetNuke:

[.NET development in Linux is] kind of silly.  A .NET programmer really needs to run Windows.  You don’t have to have server to run DNN, it will run on workstation OS’s just fine, with the limits placed on IIS by the OS.  You can easily host on a server if you need to and still develop on a workstation.

As for DNN in MONO – Yes it works.  I’ve done it.  You will lose many functions that can’t be supported, and I’ve only run it under Apache on Windows, so you still don’t win on the argument of a free Linux distro.  Basically, DNN on MONO sucks.  Big time.  But pretty much any .NET app on MONO sucks too when compared to running IIS.

If your defining choice is that you run on Linux, then you really should rethink your choice of development environments.  PHP and Java would be more apporpriate

These are just the first two I picked, because they are the only 2 Windows “Open Source” projects I knew about that weren’t listed on the Mono page. They are both a bit dated, but I think they show the attitude that Windows developers have towards Mono (and GNU\Linux).

Not counting in-house mono apps, are there any significant primary-Windows applications that are targeting Mono? Or is it more of a “it’s up to those Mono guys to provide the compatibility – if they do, great, if not, I don’t really care” sort of thing?

The attitude of Windows developers to mono, especially the perception that Mono will always trail .NET is important. Mono apologists like to say at one moment that Windows developers are a target audience, but then turn around and argue that Mono is not or does not need to “chase” real .NET capabilities. This is clearly nonsensical: you can not target a market by offering them an inferior product.If you want to attract Windows developers you have to offer them at least the same features – and likely a compelling reason to consider using non-Microsoft tools.

Furthermore, Microsoft knows this and discussed it internally. For example, from a 2005 Microsoft internal presentation given by Dan nault to Bill Gates, Steve Ballmer and others (PDF):

Maintaining Gap vs. Linux

1. Keep network effect with Applications

• Migrate applications to .NET framework
  • BUT keep framework proprietary to Windows
  • Patents required to implement clone

[...]

Maintaining Gap vs. Linux
The .NET framework contains the latest developer platform for the future, and it must be licensed like Windows. Subsets have gone about as far as they should go in the standards bodies, but we need a compact subset for phones and TVs. It was noted that we have to be careful because once the horses are out, they are out forever. At the right royalty, we can have discussions around technology beyond this.

There are many such internal documents that clearly show Microsoft understands exactly what standardizing parts of .NET means, and how to keep that offering in control and inferior to .NET. If Mono is not “chasing” .NET, then it fails to meet Windows developers expectations. If Mono is “chasing” .NET, then it both runs the risk of anti-competitive tactics on the non-standard parts, and is undertaking a task not likely to succeed.