Immediately after a disappointing Super Bowl for both football fans and commercial enthusiasts, Esurance ran an ad boasting about the money they saved by not buying a spot during the big game. Being a brand that has built itself on the principle of saving money, they decided to put their money where their mouth is. They offered the $1.5 million they saved to a random winner who tweeted “#EsuranceSave30.” Of course, given the success of the sweepstakes, you probably know this already. You were probably one of the over three million who entered.

But the giveaway and the big winner are not the real story here—not for us marketing nerds, anyway. No, the real story is the brilliance of the campaign. It used one of the oldest tricks in the marketing book, the sweepstakes, and brought it into the age of social media on the biggest possible stage. There is a lot to love about how this was done, so forgive me for the gushing…

First and foremost, the campaign matches Esurance’s image. They save money and pass on those savings to the customers, so they simply extended that attitude to Super Bowl advertising in a much more literal sense. The ad didn’t go out of its way to be funny and over the top. It was simple, witty and to the point—exactly the attitude they want to portray: no nonsense, straightforward, economical.

Entering was simple too. Just tweet the hashtag. That’s what made it the top trend on Twitter for over a day. And when people tweet about you (especially when your name is in the hashtag, a simple but important move) people will start following you. When the ad ran, Esurance’s official Twitter account had around 8,900 followers. Three days later, they were sitting at over a quarter million. If you’re not a math person, that’s an increase of 2,827 percent. Now they can reach those people with their tweets for free all the time. Add that to the great public opinion they’ve garnered with the giveaway and it starts to look like Esurance won its own sweepstakes.