That article is fucking bull. There are MANY systems at play that keep major websites online. Load distributors, round robin DNS systems, various forms of compression to keep bandwidth consumption down, etc. NONE of them can keep a substantial amount of the US PUBLIC all connecting at once from causing difficulties within the first iteration. What has happened here is simply a unintentional DDOS.
I have personally never seen a "anticipated" website launch ever take a mass hit successfully. Fuck, reddit has the same thing happen every night around 9pm
Now, as for the $643 million price tag for a website?
I don't have anything to back that up, and neither does the news article (since the contract was for extended service and for 93.7 million) follow the links and it appears to point at basically nothing.