Amazon Studios unveiled a promotion on its YouTube channel and Facebook page, aimed to garner more Prime subscribers: free viewing of the pilots of 10 original series. Among the pilots being made available on the social media platforms are the critically acclaimed, transgender dramedy “Transparent,” “Bosch,” “The Man in the High Castle,” “Mozart in the Jungle,” “Red Oaks,” and kids’ shows “Annedroids,” “Gortimer Gibbon’s Life on Normal Street,” “Just Add Magic,” “Tumble Leaf” and “Wishenpoof!”

Variety notes that all of the aforementioned pilot episodes have already been free to watch on Amazon’s website, but that putting them on social media platforms is a “new sampling strategy” and “a sign Amazon has concluded that compared with its own website and apps, Facebook and YouTube are better suited for building buzz and encouraging viewers to share and comment on the shows.”

Some of the shows are two years old, leading Variety to wonder, “why Amazon didn’t come out of the gate with a broad sampling strategy.”

Viewers who want to watch the entire season must sign up for Amazon Prime (at $99 a year for unlimited Prime Video, free shipping, and “other perks”) or “the standalone Prime Video plan for $8.99 per month.”

According to chief financial officer Brian Olsavsky, who reported the news on a Q2 earnings call, Amazon is tripling the number of original series in production, while doubling “spending on video content in the second half of 2016 versus the same period in 2015.” Spending for Prime Video content in 2014 reached $1.3 billion.

Coming back in the fall are new seasons of “Transparent,” “Mozart in the Jungle,” and the second season of “The Man in the High Castle.” Amazon will debut new shows “Good Girls Revolt,” “Goliath,” Woody Allen’s first TV series “Crisis in Six Scenes,” and “The Grand Tour” from former “Top Gear” hosts Jeremy Clarkson, Richard Hammond and James May.