Today, if you’re in a part of the world that observes it, is when Daylight Savings Time ends, and your clocks fall back by an hour. It’s a free hour of the day! Depending on how you look at it!

One question we’ve never gotten - which has always been kind of surprising - is how DST affects Project Wonderful: we charge in terms of time, so aren’t people getting a free hour of advertising when we fall back, and isn’t an hour of advertising disappearing when we spring forward?

The answer is of course no: all temporaral calculations on Project Wonderful are done in terms of “Unix time“, which is the number of seconds elapsed since January 1st, 1970. This may sound weird, but it makes a lot of things in computer science easy, including DST. Since Unix time measures the number of real seconds since this date, it’s not affected by changes to the clock: when we leap forward, we aren’t gaining an hour in any real sense. The second after the leap forward we’re still only one more second away from January 1st, 1970, and that’s what Unix time records.

I recommend checking out the linked articles on Daylight Savings Time and Unix time! They’re both really interesting, and there’s so much history and controversy and trivia behind DST that you might not expect.