MySpace did it, I will too

'... Great hackers also generally insist on using open source software. Not just because it's better, but because it gives them more control. Good hackers insist on control ...' ~ http://www.paulgraham.com/gh.html

you might run into problems ( '7. Choosing the Wrong Platform' ~ http://www.paulgraham.com/startupmistakes.html) and here (find people to work on it ~ Great Hackers, Ibid.).

Is this the server platform or client? The thing I don't get is also the extra cost in dollars. MS is not cheap.

Windows server software changed since and its now can be just the right platform as well as Linux/Apache.

Though Windows costs more, its not thousands and even not hundreds of dollars difference, its only 25-30 USD for the Windows Sever 2003 license per server. Client software doesn't matter at all.

For that price you get complete set of all required for web app technologies and tools: Windows Server 2003, IIS 6, Asp.Net 2.0, SQL Server developer edition.

In addition there is a free version of MemCached for Windows.

Where did you get the $25-$30 USD figure for Windows Server? Pricing a server at dell.com shows $799 for Standard and $3,295 for Enterprise (useful if you want more than 4GB RAM or 4 CPUs) But the OS isn't so expensive compared to SQL Server which is $5,799.00 for a Standard single processor license, or $25,009.00 for Enterprise (useful if you want all of the high-availability features).