The ubiquity of smartphones has turned spoilers into an unavoidable reality for sports fans nowadays. Due to the development of personalized recommendations, it has become easier for users to access the information they want to see, while the risk of being exposed to unwanted spoilers has increased. In Japan, where there are long working hours, 58.1% of fans of baseball—the national sport—say they have had games unwittingly spoiled for them. Sky Perfect JSAT, a satellite TV service offering on-demand pro baseball games, wanted to find a way to help their viewers avoid baseball spoilers and simultaneously increase engagement with them. Their goal was to transform unwanted spoilers into a positive experience that enhances the enjoyment of the game.

We developed a smartphone browser app that blocks spoilers and launched it in time for pro baseball season, working with Prof. Satoshi Nakamura of Meiji University, an expert on spoilers. We designed the app so that not only would it cover the screen with an animated gif if it detected spoilers, it would follow up by running an ad offering coupons for products that fans may want to buy in anticipation of the game.

Since iOS has more users than Android in Japan, we released the app on iOS. In announcing the app, we prominently featured the word “spoilers”—one of the most common social media topics. In this way, we hoped to fire up baseball fans of all demographics and appeal to their love of the game.

By extracting pro baseball terminology from text on news and fan sites and live broadcast tweets, we created an algorithm that can detect baseball spoilers. When first launching the app, the user is asked to select their favorite team and fandom level—settings that are used to determine what counts as a spoiler to the user. Every time the user visits a website, the app calculates the number of spoiler-related words and their relevance to determine the presence of spoilers. If there is a spoiler, the app blocks it with one of over 40 humorous animations.

Because the app’s launch coincided with the start of pro baseball season, the app was covered by over 170 media outlets for about 100 million yen in earned media. The app has transformed over 500,000 unwanted spoilers into positive advertising opportunities. It has also demonstrated a block rate of 99.89% and has a five-star rating on the AppStore. The success of the app has led to discussions for creating an app for other sports, such as soccer and tennis.

“This changes everything.” from Twitter.

“They made a whole app for this?!” from Twitter.

“Now make an app for soccer!!” from Twitter.