Design a referral system for Netflix to drive its user growth.

To design a referral system for Netflix focused on new user acquisition, I would consider a multi-pronged approach:

1. In-App Referral Program: Integrate a clear referral option within the Netflix app and website. Users could easily share a unique referral link or code via email, social media, or messaging apps.

   • Incentives: Offer compelling rewards for both the referrer and the referred user. This could include a free month of subscription for both parties after the referred user completes their first month, or perhaps exclusive early access to new content for top referrers.
   • Tiered Rewards: Implement a tiered system where referring more users unlocks greater benefits, encouraging sustained engagement with the referral program.

2. Content-Driven Referrals: Leverage Netflix's popular content to drive referrals.

   • Shareable Moments: Allow users to share specific clips, trailers, or even personalized recommendations directly from the platform, with the shared content including a prominent call-to-action to join Netflix.
   • Exclusive Content Access: Offer a limited-time preview of a highly anticipated show or movie to friends invited by existing users.

3. Social Integration: Enhance social sharing capabilities.

   • "Watch Together" Feature: While not strictly a referral, a "Watch Together" feature could organically lead to new sign-ups as friends experience Netflix content together and decide to subscribe.
   • Social Proof: Display anonymized data like "X friends on your network are watching this show" to encourage sign-ups.

4. Targeted Campaigns: Run specific referral campaigns around major content releases or holidays to maximize impact.

Key Metrics: Success would be measured by referral conversion rates, cost per acquisition (CPA) of referred users, and the overall increase in new subscriber numbers attributed to the referral program.