Greenspun had some great thoughts on this in 2009: http://blogs.law.harvard.edu/philg/2009/05/18/ruby-on-rails-...

Business Guy: Hands Microsoft a bunch of money, launches site on an ASP server with 64GB RAM. He is basically done with IT for the first few years of growth.

MIT Genius: Starts off trying to build a system that will scale, from the beginning. He creates about 6 months of IT work for himself. It works, eventually, but it was a lot harder than what the business guy had to do.