Bowl commercials in 2015 featuring big-name celebrities (respectively Liam Neeson and Kate Upton). The latter, Game of War, was in fact, part of a roughly $40 million campaign starring Upton. As of 2012, free-to-play MOBAs, such as League of Legends, Dota 2, Heroes of the Storm, and Smite had become among the most popular PC games. The success in the genre has helped convince many video game publishers to copy the free-to-play MOBA model. During 2015, Slice Intelligence tracked people that bought products in mobile video games, and these players spent an average of $87 in free-to-play games. The highest spending per player in 2015 was in Game of War: Fire Age, where the players that bought products on average spent $550. Comparison with traditional model The free-to-play model has been described as a shift from the traditional model, also known as premium-priced games, where consumers paid for the cost of the game upfront and the game's success was measured by multiplying the number of units of a game sold by the unit price. Within free-to-play, the most important factor is the number of players that a game can keep continuously engaged, followed by how many compelling spending opportunities the game offers its players. With free games that include in-game purchases, two particularly important things occur: first, more people will try out the game since there is zero cost to doing so and second, revenue will likely be more than a traditional game since different players can now spend different amounts of money that depend on their engagement with the game and their preferences towards it. Player populations that spend money on free-to-play games can be broken up into terms that borrow from gambling: "whales" which typically are the smallest segment, up to around 10% of players, but are willing to spend the most on a game; "dolphins" which represent a larger portion of around 40% of players who spend some money but not as much as whales; and "minnows", representing about half the population, who spend the barest amount to maintain activity. As a result of this distribution, whales typically provide most of the revenue in free to play games, and in some cases, 50% of the revenue comes from 0.15% of players ("white whales") in one report. It is not unlikely for a very few players to spend tens of thousands of dollars in a game that they