We invited Walt Hickey, author of Numlock News, to share with an audience of Substack writers in New York how he thinks about spinning off multiple newsletters for fun and profit. Walt started off with Numlock News – where he writes about the numbers behind the news – then added paid subscriptions, an Oscar Awards supplement, and a book club.This transcript has been lightly edited for readability.TakeawaysMultiple newsletters are a lightweight way to experiment with new ideas.Use your main newsletter to create spin-offs, so you never have to deal with the “zero subscriber” problem again.Get creative with your paid subscriptions. You don’t just have to send one free and one paid post. Depending on your topic, you might consider publishing paid content during a peak season, quarterly in-depth reports, or more.I run a newsletter called Numlock. It’s a daily morning newsletter about the numbers inside the news.I started it after working at FiveThirtyEight for about five years, where I’d started a newsletter called Significant Digits. As a guy with a math-y background, I realized that my biggest liability as a person in journalism was that I needed to get better at writing, and doing something every day was a really effective way of practicing.I really enjoyed writing that newsletter, and then it hit a point where the scuttlebutt was that FiveThirtyEight was going to be sold. I looked at where Sig Dig was and realized there was more value in there than we were currently unlocking. The open rate was great. People enjoyed receiving it. In building the case for why FiveThirtyEight should keep me, I actually built the case for why I should leave and start my own newsletter. I did that, and it's been great.How he started multiple newslettersMy main newsletter is Numlock, it’s my bread and butter. It’s what I've been doing for more than two years now. I have a product that I think is good, and that my audience thinks is good. As a result, I have a good “in” with people who enjoy reading my work. If I were to describe Numlock in Uber-for-pizza terms, what I think of is, “It's Good Morning America for nerdier folks.”This being Substack, at a certain point, it came time to monetize, so I launched a Sunday edition. For $5 a month, I talk to either a writer who wrote a really cool story that I put in the main newsletter, or I talk to an author who's got a good book out. This is a really fun way to add value.If you think about traditional media ecosystems like late night shows, there’s a reason they have written jokes in the beginning and then an interview at the end. It’s because interviews are easy to book, and people tend to like them a lot. It’s a nice way to have something that’s less work than the newsletter itself, but gives people more insight into the stories that we find.But I’ve also started a couple of other spin-off newsletters, one of which is the Numlock Awards Supplement.I’m a culture writer, and I love predicting the Oscars using math. It's a good time. I started about two years ago and wanted to keep doing it. I think we learn a lot about ourselves, and how we can predict things, through this institution that is very obscure. It's a fun little puzzle.So I started a pop-up award season newsletter. It runs from November-ish, or whenever I feel like starting it, until Oscar night and the week after. It's a nice opportunity to talk about a thing I'm really passionate about, but not have to throw it at my traditional people who just want to watch Good Morning America and never talk to me again.That spawned another idea. I love engaging with audiences, and discussion threads are such a cool feature that Substack has built. I wanted a way to tap into that without compelling people who just enjoyed the passive nature of newsletters to participate.So I thought, again, having interviewed a lot of authors and seeing the response that that gets, my audience is one that enjoys reading things, learning new things, cool ideas, cool books an