The service disruption at Google on Thursday morning caused a 5% drop in Internet traffic, underscoring the extent to which Internet users and other Web sites depend on the company.

Arbor Networks chief scientist Craig Labovitz observed in a blog post that failures happen. "[B]ut if you happen to be Google and your content constitutes up to 5% of all Internet traffic, people notice," he said.

People did notice and complained loudly. Blog posts proclaimed Google's failure. Twitter jittered with tweets. Lattes languished undrunk on office desks as workers muddled through life without Gmail.

As a consequence of Google's problems, business Web sites that depended on services like Google Analytics took twice as long to load on average and were twice as likely to fail, according to Web infrastructure management company Gomez. And among online retailers, transactions took four times as long as usual to complete.

Google was quick to apologize. Senior VP of operations Urs Hoelzle explained the situation on the Official Google Blog. He said that a routing error had sent some of the company's Web traffic to Asia, causing a bottleneck that affected 14% of Google's users.

In an effort to express networking arcana in common parlance, Hoelzle described Google's service snafu in terms of air travel, the universal touchstone for misery and despair.

"Imagine if you were trying to fly from New York to San Francisco, but your plane was routed through an airport in Asia," he said. "And a bunch of other planes were sent that way too, so your flight was backed up and your journey took much longer than expected. That's basically what happened to some of our users today for about an hour, starting at 7:48 am Pacific time."

The beauty of Hoelzle's air travel metaphor is that it makes what did happen look pretty good compared with what could happen when talking in terms of planes. At least Google's downtime didn't leave anyone stranded in a sweltering cabin on the tarmac without food, water, or restrooms for nine hours, or free-falling without engines.

Imad Mouline, CTO of Gomez, prefers a water metaphor, noting that Google's outage had a ripple effect on Web sites that depend on its services. As he put it in a statement, "The impact of Google's problems demonstrates the complexity of today's Web sites and their susceptibility to performance issues when third-party content or service providers experience problems."

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