Broadcast media giant Viacom is making a serious investment in its streaming future. The conglomerate is buying streaming service Pluto TV for $340 million.Viacom has long been a major player in the world of media. It owns TV channels like Comedy Central and MTV, as well as film production companies like Paramount Pictures, one of Hollywood's “Big Six” film studios. Viacom has watched other media companies make big moves into streaming — none bigger than Disney's acquisition of the bulk of 21st Century Fox. Viacom's move isn't on that scale, but it may help the company control its own streaming future.Pluto TV is a free streaming service that makes its money on ads. But it's not “ad-supported video on demand” (AVOD) service like Tubi TV or Amazon's new FreeDive service, exactly — instead of on-demand content, Pluto TV offers a selection of continuously streaming channels. For the most part, these channels are not the familiar ones you'd see on other multichannel live TV streaming services like Sling TV and Hulu with Live TV. Pluto TV develops its own channels and their playlists using content that Pluto TV licenses out, plus content that is already freely available on the web.Pluto TV's ad revenue may have appealed to Viacom, but this acquisition doesn't necessarily mean that Pluto TV's model will remain the same. A big part of Pluto TV's appeal is its presence on major streaming platforms like Roku, Fire TV, and Android TV. Pluto TV claims to reach 12 million users, 7.5 of whom watch on TV screens (using, presumably, those streaming platforms). With this acquisition, Viacom can put its content on a platform that already enjoys a presence on major platforms and a foothold in the viewing habits of millions.Viacom's move also allows it to follow the sort of vertical integration model that Netflix has pioneered and which other streaming and media companies have aggressively followed. These companies have found that they can make more money when they own their own studios, content, and streaming platform. Viacom can now produce a movie through Paramount Pictures or a TV show through MTV and then keep its streaming rights in-house. Whatever Pluto TV may look like in terms of subscription or advertising model a year or two from now, you can expect it to feature a whole lot of Viacom's own content.