I agree with some of this. I think XNA export would be huge, insanely huge even, but I don't think android or iphone are fads. iphone is obviously huge, and jobs knows how to innovate just in time to avoid death. the iphone will get awesome again, and android is only beginning, every month there's like 5 new WOW I WANT THAT phones that are android based. just using it, and knowing google, are enough to know it isn't going away any time soon. during c2 development it will be clear if windows mobile 7 emerges as the supreme leader or not, though, which could easily happen, which once again, makes XNA a good candidate. like I said, I agree with that part, but I think the cell phone thing is only just beginning.[/quote:jvli2yez]
I'm not saying cellphones or the mobile gaming format is a fad, those are well-established and here to stay. But Android, iphone, ipad, KIN (already dead and it only took a few weeks to get its plug pulled), even Windows Phone... will all be long dead, obsolete and buried for years before XNA and the C# language even gets a speck of dirt on its skin. Plus, you're right that the cellphone craze for gaming is just beginning in this realm, but that bolsters the XNA point even more. XNA is already there and has been there for a long time and only continues to expand its reach.
Don't get me wrong, I'm not saying Android or any cell export would be bad, it's just that you'd be picking a trendy format with a far smaller reach, over a much larger more established one with a hugely long reach that's positioned to be around for a long time just because of its scope and the language its built on.