What are examples of viral loops?

Common examples include referral links (invite a friend, both get a reward), social sharing built into the product (a shared document or design that exposes new people to the tool), and waitlist queue-jumping where inviting others moves you up the line. Dropbox's referral program and Robinhood's waitlist are textbook cases.

Can a waitlist alone be a viral loop?

Yes — if it gives each signup a reason and a tool to invite others. A plain email-capture page is not a loop, but a waitlist with referral links, queue position, and rewards turns every signup into a potential source of more signups, which is exactly what a viral loop is.

Viral loop — Waitlist Glossary

Viral loop

A viral loop is a closed cycle where each new user produces actions — most often via referral links, shared invites, or built-in social sharing — that bring additional users into the same product.

How it works

A viral loop repeats three steps: a user joins, the product gives them a reason and a tool to invite others (a referral link, a share button, a "skip the line" incentive), and the people they invite enter the same loop. The tighter and faster the cycle, the more compounding growth it produces.

Why it matters

Viral loops are what let a waitlist grow without paid acquisition. The strength of a loop is measured by its K-factor — when each turn of the loop produces more than one new user, growth sustains itself.

Related terms

K-factor — K-factor is the average number of new signups each existing user brings in through referrals, calculated as the share of...
Viral coefficient — Viral coefficient is the measure of how many additional users each user brings into a product through referrals; in grow...

Frequently asked questions

What are examples of viral loops?: Common examples include referral links (invite a friend, both get a reward), social sharing built into the product (a shared document or design that exposes new people to the tool), and waitlist queue-jumping where inviting others moves you up the line. Dropbox's referral program and Robinhood's waitlist are textbook cases.
Can a waitlist alone be a viral loop?: Yes — if it gives each signup a reason and a tool to invite others. A plain email-capture page is not a loop, but a waitlist with referral links, queue position, and rewards turns every signup into a potential source of more signups, which is exactly what a viral loop is.

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