I have a posting in me somewhere about the significance of internet-scale applications and their impact on software development but for some reason I can't get it all out. So I thought I'd post a placeholder anyway, just to prove that I was thinking about it.
Summary is that Internet has now exceeded Enterprise as the gold standard in software - platforms like Amazon, Facebook, Google, Yahoo etc. have pioneered ways of working and architectural patterns that make traditional "n-tier" enterprise applications look like toys.
Expect more soon, once I've worked my thoughts into some logical order.