They just told me in an email, and I just canceled my subscription.
I didn't appreciate the way they did it: No explanation of why the increase is necessary, plus idiocy like: "Your price for getting both of these plans will be $15.98 a month ($7.99 + $7.99)." No package discount, and no consideration for having been a loyal customer for six years straight. No, just a form letter and a 60% price hike.
Their post-cancelation survey offered no way to indicate this change as the reason (and no free-form entry). Didn't they anticipate this? Maybe they don't want to know.
This makes me sad. I love Netflix. I'm not saying it's not worth $16/month, and I may even join again someday. But I hope a few million customers slap their corporate hand.