It's really funny because when I started working on the demo I had a full slide deck. Each time I practiced I eliminated a slide or two until there was nothing left. At that point I decided to just show the site and start coding.
You'd be astonished how magical "I can make your phone ring" feels to people. Family, friends, and people who don't even know me giggle when I do my demo on them.
It's even better if it's a business pitch rather than a technology demo. The world's best sales pitch is always being able to say, "If I push this button then your phone is going to ring 150 times in the next 3 minutes with people who want to buy your product, want to see?"
That's how you get to charge 150K per client per year, and that's why DailyCandy and the like are worth so much.
He used nano and PHP, and I think that was a strong tactical choice. It shows how you don't need anything sophisticated to use Twilio. If he pulled out NetBeans with J2EE, or Visual Studio or Emacs with Rails, people will be suspicious there might be some "magic" happening behind the scenes.
Nice that he was able to overload an entire cell tower during the demo.
This is actually pretty similar to our demo at NYC Tech a few years back: Showed the product, let everybody jump in live, brought down the venue's wifi. Fun times:
HOLY COW. That was the fastest programming I've ever seen. Haha - loved it when the room full of nerds corrected John on the one typo he made with the semicolon. Hilarious!
Good demo, yo!
What an amazing demo. Love the way the audience got involved in the coding ("semi colon!!!") and the interaction between you and everyone in the room. Steve Jobs is in trouble.
The product was an API, Application Programming Interface. To demo it properly, you have to do some application programming. Your question applies to any product that the VC wouldn't use her/himself..