Tom Scott
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I Know What You Did Five Minutes Ago

Details

Performed at Ignite London 4: in which I rattle through the online privacy settings of fashionable web services, and leave a surprising message.

Frequently Asked Questions

Is the data really pulled in live from the web?
With the exception of the Wikipedia articles, which I summarised in advance, yes. Everything on screen really was live data.
Did you know who was going to appear?
No — but the selection process was algorithmic, not random. It was always going to pick someone interesting. As an extra safety net, a few minutes before I went on stage someone else checked who the system had chosen: they forced a re-selection if it picked someone under 18, someone in the middle of anything stressful or traumatic, or someone who appeared likely to react badly to the phone call.
What presentation software were you using?
Google Chrome, running a regular web page written with HTML, JavaScript and jQuery. The data was pulled in using the sites' official APIs, with the exception of the live Facebook profile. Facebook has excellent security and will not let you put its pages inside an iframe; so another computer took a screenshot of the profile and uploaded the result as a PNG.
How did you do the day-of-the-week calculation?
I used this method, taught to me by the wonderful Dr James Grime. As for the speed, I was exceptionally lucky: the date was a very easy one to calculate.
Did the person you called ever call back?
Nope. But then, I did drop that disposable phone in my glass of water at the end of the talk.
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