Working Session: Growing Substack with Referrals

I heard Packy McCormick was using referrals to grow his substack, so we set up a working session to dive into the program.

The result is this video which goes into lots of details. Please subscribe on YouTube. I put a timed transcript below, along with the notes I used to prepare for the session.

0:00 Introduction

0:26 What is "Not Boring"?

2:21 Who is your audience?

3:11 The goal is growth, while retaining quality.

4:35 The economics of syndicates vs fund

7:08 How to configure content for premium vs free subscribers

9:45 Exploring the new DIY media trends

11:30 Writing about small vs large companies

12:22 What tools do you use for your Substack?

14:25 Webflow vs other landing page tools like

15:50 Ivan's stack at

16:55 How does Growsurf help?

19:20 Start diving into the user flow

19:55 Guessing Hunter Walk's name on the leaderboard

20:30 Powerlaw distribution of the referrer leaderboard.

21:15 Launching your Substack on Product Hunt

22:55 Ivan Kirigin's background helping run growth at Dropbox and founding YesGraph to help startups grow

25:45 Getting subscribers vs getting referrers, and optimizing the related call to action

27:15 What to send in a welcome email? Too many links is confusing.

28:40 Feature request: AB testing calls to action in Substack welcome emails. How Dropbox ran AB tests for referrals

31:00 How stickers and t-shirts are surprisingly motivating.

31:25 Don't make the user do more work. For example, if you already know who they are, don't ask for their email again

32:35 Why the referral sharing channel matters. You could break down successful shares across channels like Facebook, Dropbox, and Twitter

34:45 The challenge of writing copy that will put words in a user's mouth

36:15 Why importing contacts and send-all is bad. Ivan shares a story from Dropbox about removing send-all.

38:00 Personalizing landing pages helps improve conversion.

39:25 How social proof improves landing page conversion.

40:15 How to break down startup metrics.

42:45 Why to measure viral loops continuously not in average aggregate.

44:45 How Substack building their own referral features would help the ease of the flow.

46:45 How tracking invites helps optimize the flow.

47:15 Why the biggest mistake is not promoting the referral program enough.

48:45 What should Substack put in a referral program? After including a referral link, earning a paid subscription would be incredible.

50:40 Allowing you to test which posts bring in the the most new users.

51:50 How good content matters for the amount of growth, with Y Combinator's YouTube channel used as an example. 1/3 of all their traffic is from 3 videos about Elon Musk and Mark Zuckerberg.

Profile Link (or tweet, or elsewhere)

Two links: domain and substack.

Substack landing page

Obvious goal: subscribe

Individual Post Landing Page 

no links to referrals

Subscribe Email

link to referrals, with 6 other links

Referral sending page

  • Slow to load

  • No way to participate above the fold, but obvious to scroll

  • Not obvious those are stickers to win

Enter email form to participate

This is an extra step. Many already have given you the email, you’re just not saving it.

Referral message

  • Nice subject

  • Clear call to action

  • Editable by user, without the UI

Referral landing page == subscribe page

  • Who is the inviter?

  • Subject works no matter who invited

  • Product hunt general social proof, along with “6000+”


These are for each time period, meaning they are a loop

  • On referral program / all subscribers # put links in newsletter - or their referral link

  • Invites / inviter # is this transparent in GrowFlow? Your analytics? Eg URL grsf=*

  • New / invites #

Specific Metrics

Track total referrals right before each newsletter is sent.

Put each in a spreadsheet, with (date, total, new).

Include total subscribers to get 

  • aggregate growth rate: new subscribers / total subscribers

  • total referral growth rate: new subscribers from referral / total subscribers 

  • percent of growth from referrals: new subscribers from referral / new subscribers

Interpolate if you need to get standard dates, eg weekly referral growth

Run longitudinal AB tests on (positioning, copytext, color) of referral prompts

  • If total referral growth rate increases, good

  • Even if percent of growth from referrals increases: good

  • Caveat: longitudinal tests will have conflating variables. Examples:

  • Marginal subscribers might default to lower referrer rates. 

  • Marginal potential audience might be less eager to subscribe, lowering all channels

  • Your content varies!