David Cowan has a great post summarizing a presentation he made at Babson College. My take-away:

And so the winning recipe today for aspiring entrepreneurs is GET BIG CHEAP.
Don’t waste expensive development on untested ideas, and don’t let a
fat marketing budget mask a weak value proposition. If instead you
tinker your way to scalable organic growth, you’ll have a valuable
business on your hands. Don’t worry about how long it takes—just make
sure your burn rate is low enough to accommodate several cycles of
iteration.