The deal involves licensing hundreds of hours of programming from Viacom cable networks such as MTV, Comedy Central, Black Entertainment Television and Spike, as well as movies made by the company's Paramount studios, the companies said.
The companies declined to disclose financial details. In similar deals in the past, Viacom has received two-thirds of the advertising revenue and other compensation, The Wall Street Journal reported.
Key to the agreement was Joost's promise it would protect Viacom's copyrights, Viacom Chief Executive Officer Philippe Dauman said. This stumbling block led to the collapse of similar talks with YouTube parent Google Inc. two weeks ago.
Unlike YouTube, which carries mostly short video clips uploaded by users, Joost's strategy is to run full episodes with high-quality resolution, like TV but online, Joost said.
"We built this platform from the ground up, with companies like Viacom in mind," co-founder Janus Friis said.
Joost, originally called the Venice Project, was started last year by Friis and Niklas Zennstroem, who created the Kazaa file-sharing network and Internet phone service Skype, now owned by eBay Inc.