Launch a referral program that rewards subscribers with perks

Set up a referral tool such as SparkLoop or a built-in Substack referral program, and give each subscriber a unique link to share. Offer a small reward at set milestones, such as a bonus post or extended archive access, when someone refers three or ten new subscribers.

Why it works: Existing subscribers already trust your judgment, so giving them a concrete reason to share turns them into your lowest cost acquisition channel.