Yesterday evening Khan Academy was featured on 60 Minutes. It was a rerun.
Ben Eater recorded our real-time active visitors during the East Coast feed
— here it is sped up 10x.
In March, when the clip first aired, I had Camtasia open and was recording my view of Google Analytics’ real-time visitor data. I was excited to share a view into the traffic Sanjay Gupta commands when he’s not neurosurgeoning or professoring. So the segment starts, we see 10k simultaneous visitors…12k…20k…30k…45k…50k…I test a quick load of the homepage…crash. Try again, crash. Fast forward three fire-fighting hours later, and I would barely remember that I left Camtasia recording the whole thing. I wound up with more video than anyone would ever want of me tabbing around like crazy, trying to help our site scale.
We wound up dropping at least 30% of the East Coast feed’s homepage requests on the floor that night. Rough. We barely managed to patch things up before the Mountain and Pacific showings.
Needless to say, we were excited when 60 Minutes gave us the heads-up earlier this week that they’d be running the piece again. We started twisting all the pre-traffic dials we learned about during our struggles last time (tech details are out of scope for this post, lemme know if you’re interested) and crossed our fingers. Our site has changed a lot since March, so we were obviously at risk of unknown scaling issues. But more importantly, Craig, Chris, and Dylan spent the summer battening down our App Engine hatches with a focus on performance and reliability.
Yesterday’s requests per second
The steepness of this spike isn’t helped by the fact that this aired on the
Sunday before a holiday, which means the rest of the day had very low traffic.
Things went quite well this time. We were shy of perfect — right at the peak, we dropped about 500 homepage requests due to a slight problem that we’ll know how to prepare for next time — but handled the traffic much, much better than last time. All in all, we saw over 1.2M pageviews from the start of the East Coast feed at ~4:30PM EST to the end of the West Coast feed at ~8PM EST. That’s over 1/3 of the pageviews that POTUS got on the day of his reddit IAMA — a cheap, unfair, ridiculous comparison since we’re counting pageviews across our entire site vs. a single reddit post, but, hey, politics aren’t fair. Again, much credit to App Engine and our App Engine team. All I did was yell out “50K!” ceremoniously when the concurrent users counter ticked past fun milestones.
Last March’s Sunday visits:
Our visits peaked much higher during the original airing…
…but the rerun still delivered quite a bit of traffic for us.
On August 14th we launched our new computer science section of Khan Academy. It was featured by venturebeat, Techcrunch, Wired, Forbes, and more. John’s blog hung at the top of Hacker News for almost an entire day, and twitter was exploding with positive feedback. Despite being a massively successful launch, that amount of online press didn’t come close to the traffic that 60 Minutes has at its fingertips. It’s not a perfect comparison since John’s blog likely soaked up a lot of traffic, but it’s still interesting.
In fact, looking back over a couple years of Khan Academy traffic, no press event has even remotely approached the original 60 Minutes airing’s traffic spike. Yesterday’s rerun and Sal’s TED talk are the next most interesting events.