There are startups using .NET, but they aren’t the majority, and those who chose to do so are buying themselves into a trap with expensive licenses and a locked-in platform.
Jeremy Wright from b5Media, who has a great blog called Ensight, contradicts him:
The startup can grab ISV packs which’ll cost about 2500$ to get the company up and running with all the dev tools and server bits they’ll need. Toss in another 2500$ and they’ll get all the MSDN stuff they need. 5000$ is not that much to get a 5-10 man shop up and running, even when bootstrapping.
Jeremy has a great point, but he's off by an order of magnitude!
I work at a startup. We joined Microsoft's Empower program, which exists to help startups with initial costs. It cost us $375. It included a universal MSDN subscription with 5 user licenses, as well as 5 licenses for Office, and "the full array of server products including Windows Server 2003, Exchange 2003 Server and SQL Server."
Um, does $375 seem like an exorbitant amount for that?
Also included: technical support and training. Individuals at Microsoft assigned to help us with technical details, our marketing, and even our sales.
As soon as we could, we became Partners, then Certified Partners, then Gold Certified Partners. The benefits are enormous: Microsoft helps with marketing, they help with architectural issues, we get early releases of software, we get direct access to the product teams and their roadmaps. Oh, and we get GREAT license benefits.
If you haven't worked with Microsoft, then you just don't understand this: they work very, very hard to create an ecosystem that actually fosters innovation. They want startups like mine to choose their tools, so they do a tremendous amount of work to make it a good choice. And with programs like Empower, the cost of all those tools, operating systems, and support, is virtually nothing.
Windows may not be your OS of choice, and if your users are all running Linux boxes, obviously these tools and programs aren't for you.
But if you think it's too expensive for a startup to use Microsoft products, you just haven't done the research.
From our perspective: it's a slam dunk.