In the past, developers and publishers were often reluctant to release an open beta of a game, fearing that the public would get the wrong impression of a game that was still under development. That began to change after Blizzard discovered that, with World of Warcraft, testing periods helped promote the game through word-of-mouth while the developers steadily improved the experience. This is a formula that was repeated with hits like Heroes of the Storm and StarCraft II: Legacy of the Void, and is sure to be repeated with the upcoming release of Overwatch. Furthermore, with the rise of crowdfunded projects and Early Access, the gaming public is now relatively accustomed to playing games that are still in development, and are often eager to get a sneak peek of an upcoming game, and may overlook the flaws if it means that it will lead to a better game on release.

Recently, hosting closed and public betas for high-profile games is practically expected, especially if they feature multiplayer. The most recent example is today’s reveal of Doom‘s multiplayer gameplay and the announcement of its closed beta session running from March 31st to April 3rd, which will no doubt stoke fan fervor leading up to the May 13 release on Xbox One, PlayStation 4 and PC.

Hosting a beta, particularly an open one that anyone can participate in, is a win-win situation when promoting a game. Although participants are likely to run into flaws, the event gives developers a chance to identify and fix them. At the same time, participants freely promote the game through livestreams, social media, and discussions. Last fall’s Rainbow Six Siege closed beta was extended due to server issues, which helped make for a smoother experience with the open beta, which acted as a big lead-in to the game’s launch.

However, the power of using a beta period to stir up hype is clearly shown by how the Call of Duty: Black Ops III beta was clearly used as both a promotional and data gathering tool. The game went on to make over $550 million in the first three days of its launch.

Last fall, the Star Wars: Battlefront open beta broke records by drawing in over 9 million players worldwide, which turned the testing event into a barometer of interest. Similarly, the recently released Tom Clancy’s The Division drew in 6.4 million players during its 3-day (four for Xbox One players) open beta period. The game ended up selling “more copies in its first 24 hours of availability than any previous title in the company’s history,” according to an official statement from Ubisoft.

EA discovered the value of giving players an early look at games, since these trial periods not only lead to a better game while promoting it at the same time, but also project a sense of transparency regarding its development and its features. Last year’s Battlefield Hardline saw multiple preview and testing periods, starting with its reveal at E3 2014, which helped get the word out about the game. The final beta leading up the game’s launch saw 7 million players that couldn’t wait to play cops and robbers on a large urban scale. This transparency could lead to a greater sense of trust, as developers get valuable data and feedback from fans, and players learn first-hand what to expect from a game before it releases.

Although beta periods are primarily used for testing, they are spectacularly useful as promotional demos. Halo: The Master Chief Collection offered early buyers access to the first Halo 5: Guardians multiplayer beta. Similarly, those who purchased Uncharted: The Nathan Drake Collection were allowed access to Uncharted 4: A Thief’s End‘s multiplayer beta last December.

With high profile games like Doom, Homefront: The Revolution, Battleborn and more releasing this spring, it becomes ever more important to get them into the hands of players so that they can promote them through discussions and livestreams. It also doesn’t hurt that feedback improves the game.