10k, really?
Not that I fully understand how your theory works, but 10k isn't going to get you an inch off the ground if you want enterprise class gear.
Unless you don't believe in speed, reliability and redundancy.
I don't make things up :) And we always put 2 in for redundancy!
Here's some CoLo prices, too:
http://www.redstation.com/colocation.html
So, figure at least £1400pcm for a single rack in a single data centre. There's probably loads of extras you'll need too.
But whatever, Pete - we clearly disagree on a number of things such as "industry standard" and "world class".
Well, firstly, I don't believe you can run something that big on rented hardware. Facebook has over 800 million users.
Let's say you store just 500 kilobytes of data per user. That's
800,000,000 * 500 = 400,000,000,000 kilobytes.
400,000,000,000 kb = ~372 Terabytes of storage alone.
Secondly, even if it as all rented and managed by someone else - you're still going to pay for it!
I just think Pete's got his head in the clouds on this one.
I have a feeling it's going to involve some kind of peer - peer stuff where bits of data are stored on peoples machines or some such. Even ignoring the security issues there, I still think it would be horrendously unreliable and I don't know what happens with mobile stuff.
I just Pete has massively underestimated what it genuinely costs to run something on the scale of Facebook. I don't doubt one could write a better platform and so on, but I think they'll all get cold sharp shocks when they try and scale it into the millions of users.