While known for virality, Zynga's core success metric was Day 365 retention. This long-term focus forces teams to build durable value and answer 'why would someone use this in a year?' This creates a more resilient product than those chasing short-term growth hacks.

While the goal is often a frictionless experience, some friction can be a positive filter. Descript found that users willing to download a desktop app were more invested and more likely to stick around. Don't be afraid of early steps that test a user's commitment.

With app discovery effectively dead (average zero new downloads/month), Mark Pincus contends that the critical metric is Day 365 retention. Your product's initial experience must convince a user not just to try it, but to envision it as part of their digital life a year later.

While it's easy to get users to try new AI products, this only amplifies the importance of retention. The core challenge isn't awareness, but building a product so indispensable that users integrate it into their daily lives and won't go back.

The biggest initial hurdle for a new product isn't getting the first dollar of revenue; it's crossing the chasm from a user trying the product once to becoming a truly engaged, repeat user. This "penny gap of engagement" is the most critical early milestone to overcome for long-term success.

Zynga succeeded not by making games "viral" for acquisition, but by designing social loops (like gifting) that created social obligations. These mechanics were fundamentally retention tools, using social networks to remind friends to come back and play together.

Despite massive initial growth, HQ Trivia's user base churned because the core product remained unchanged. The leadership team, lacking mobile gaming experience, failed to ship new features or engagement mechanics, leading to predictable user fatigue and a massive drop-off in players.

Retro's emotional onboarding video caused a 20-30% signup drop-off. While seemingly a failure, this friction can act as a valuable filter, weeding out low-intent users and attracting those who resonate deeply with the product's core mission from the very beginning.

Wordle went viral not because of complex features, but because of their absence. By removing all barriers to entry (no app, no login) and adding a simple, spoiler-free sharing feature, it created a frictionless experience that fueled its explosive growth.