Viral growth requires not just a good product but also an excellent user experience that encourages users to share it with others. A strong referral program is essential for facilitating this growth.

There are three types of growth: sticky growth, which focuses on retaining existing users; viral growth, which relies on users referring others; and paid growth, which involves spending money to acquire users.

A simple and easy-to-use product encourages user retention and can lead to viral growth.

Virality occurs when one user introduces your product to others, while network effects mean the product becomes more valuable as more users join. Successful consumer companies leverage both to grow their user base organically.

If your product is social in nature, having more users improves the experience, making it essential to focus on virality and referrals.

Word-of-mouth growth is the most effective form of marketing; create a compelling story about your product that users want to share.

Organic growth, which is growth that doesn't require payment, is often neglected by founders. For example, at Monzo, we reached a million customers before spending on direct marketing or advertising, primarily through virality and network effects.

Great consumer companies that achieve significant scale typically optimize their viral loops and network effects to ensure the majority of their growth comes from organic channels.

The best companies grow through word-of-mouth rather than paid acquisition, and in the early days of a startup, if you lack funds, focus on growing your business without spending money by doing things that don't scale. This organic growth is a sign of a strong product that resonates with users.