Twelve years is an eternity in Internet time. We didn't have Twitter, Facebook, or Instagram in 2001. Still, when the Twin Towers fell, Americans flocked online to get information about one of the decade's biggest news stories.

At the time, Livejournal was already two years old. Xanga had just started offering photo uploads. AOL Instant Messenger was preparing to launch a service for Nokia phones.

Despite how limited some of these services were — user-generated videos a la YouTube were still four years away — Sept. 11, still produced an incredible amount of data. Andy Ellis, chief security officer at Akamai, recalls that before the Twin Towers came down, the traffic routing company had only ever moved, at most, 6 gigabits of data per second.

Then MSNBC decided to stream its program live on the Internet, which drove the cable channel's data usage past all previous Akamai records. MSNBC had hired the company to handle just this problem, and as the data usage mounted, Akamai noted that MSNBC's Web site was moving 12.5 gigabits of data per second. (For perspective, the entire country of New Zealand today uses 120 gigabits per second of bandwidth at peak hours, according to Kim Dotcom in a recent interview.)

For some, the Internet slowed to a crawl. Jackie Mathis was a high-school student in North Carolina when she learned of the attacks in New York. In response to a tweet this morning, Mathis told me the Web became virtually unusable because of the load.

"There I am, trying to get any information from Yahoo and CNN, but the Web sites would only load intermittently," Mathis added in an e-mail. "Our computers were dial-up modems, and there was just too much traffic. So all we had was the TV."

In an age of dial-up and DSL, it probably should have been no surprise that the Internet went down, just as cell phone networks did. But some news outlets got creative in anticipating the extra load, says Akamai's David Belson.

"I believe it was CNN whose network folks were smart enough to say, 'Hey, we need to shrink our content so that it's small enough to fit in one data packet,'" Belson recalls. "It was a barebones, text-based page, very basic but informative. Instead of overloading their network sending multiple packets, they were able to make it very efficient."

Internet infrastructure wasn't the only bottleneck. Individual Web sites and services were caught flatfooted. The FBI, which had posted mugshots of the Sept. 11 hijackers within hours of the attack, also buckled under the extra traffic. The agency suspected at least some of it was malicious — opportunistic hackers launching denial-of-service attacks and causing other mischief.

Internet companies have learned a lot in the 12 years since. Now they routinely adapt to major news events with the expectation that people will flock to the Web to find out what's happening — and to participate in the news-gathering process.

"Whether it's the royal wedding or the Olympics or Black Friday — there's always going to be some event, either planned or unplanned, that will generate an inordinate amount of load," Belson said. "The question is how well you've prepared for that."