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.

To achieve virality, your product must inherently encourage sharing from day one, rather than treating sharing as an afterthought.

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

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.

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

Virality can be engineered rather than being purely accidental; consistent success comes from understanding what works and applying that knowledge.

Viral growth occurs when users have such a great experience that they recommend your service to others, leading to organic growth without additional costs.

At Y Combinator, we advise founders to focus on creating a product that 100 people love rather than something that 1 million people merely like, as those 100 passionate users can become your viral sales force.

Creating internal virality within a company can help align teams and generate excitement about new products.