Startup Growth

In the YC course, growth comes after product love. The strongest recurring claim is that retention is the foundation: if users do not stick, growth tactics only pour more users into a leaky bucket.

Retention first

Alex Schultz argues that retention is the single most important growth metric. A viable product has a retention curve that flattens above zero for some target segment. If the curve trends to zero, the company should fix product-market fit before hiring growth specialists or optimising virality.

North Star and magic moment

Growth needs a company-level North Star: Facebook used monthly active users; WhatsApp used sends; Airbnb used nights booked; eBay used gross merchandise volume. The North Star should make trade-offs obvious when founders are not in the room.

The magic moment is the experience that makes the product's value click: seeing friends on Facebook, finding the unique item on eBay, or staying in a compelling Airbnb. Growth work should get users to that moment as fast as possible.

Channels and tactics

Adora Cheung divides growth into:

• Sticky growth: users return because the experience is good; measured via retention and CLV.
• Viral growth: users tell or invite others; depends on product love and referral mechanics.
• Paid growth: spend to acquire customers where CLV exceeds CAC and payback is sustainable.

Alex Schultz adds tactical levers: virality, SEO, email/SMS/push notifications, internationalisation, and marginal-user optimisation. But he is explicit that these only work after retention exists.

Founder 80/20 addendum

Founder 80/20 Principle reinforces this page's retention-first frame: growth leverage is mostly retention over acquisition, word-of-mouth over paid ads, and friction reduction over incentives.

North Star check metrics addendum

Gokul Rajaram adds that a North Star metric should indicate both customer value and company growth, but it must be paired with check metrics. Revenue alone is usually a poor North Star; better metrics describe useful customer behaviour, such as DAU, GPV, GMV, or volume of valuable work completed. Check metrics prevent the team from maximising the North Star by destroying margin, retention, trust, or customer health.