There's some guesses in here, but the title is rather misleading. No one still knows why these routes are no longer being advertised, only that they're not.
The blog post also makes mention of traffic being disrupted a couple of times on varying scales before this major outage occurred which kind of signals that they were testing bringing the whole Internet down beforehand.
Which I think is more likely, considering the relatively few points of failure.
http://thenextweb.com/me/2011/06/07/this-company-is-helping-.... http://www.thestar.com/news/canada/article/1218965--guelph-t....
They have previously been used by Egypt to close down their internet. I have no insight into how this particular incident was accomplished, but this sort of software is where I'd start looking.
The interview itself was interesting. The technical tests etc were relatively trivial, mostly stuff you'd expect about load balancing and responsiveness (as would be required for routing software). But more than half of the interview was them pitching the company to me -- they're quite aware of the reservations people might have about working for a company whose direction is to suppress free speech.
Their basic pitch was that they believed all 1st world governments would have internet filtering technologies in place in the near future -- that governments would legislate the use of it to stop the proliferation of things like child pornography, and eliminate the zombie-computer defence -- that if there were child porn on your computer, you went and got it.
We talked a little about the technical challenges of instantly shutting down the internet of an entire country, like Egypt, but they more or less blamed that on "improper configuration" of settings. At one point in the interview, the interviewer told me that you have to believe that the people that make the weapons aren't the ones firing the guns, and that dangerous tools can be used for good, but that yes, there were nights in which he cried himself to sleep.
Super interesting interview.
That leaves a few options of how to shut off the internet of a country, and they give a pretty plausible one, and who would have the authority/power to do it. And they back it all up with evidence.