Which streaming service first introduced the concept of 'churn rate' as a critical performance metric for the film & television subscription model?

The film and television industry has been transformed by subscription-based streaming services over the past decade. What began with Netflix's pivot from DVD rentals to streaming has evolved into a multi-billion dollar battleground with dozens of major players competing for viewers' attention and monthly subscription fees. This poll tests your knowledge about a key financial metric that shaped the industry's subscription model strategies.

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HBO (with HBO GO in 2010)
Netflix (in their 2007 shareholder letter)
Hulu (during their 2008 beta launch)
Amazon Prime Video (in their 2011 annual report)