Substack

Substack is an online platform that provides publishing, payment, analytics, and design infrastructure to support subscription newsletters.
Content.
Substack users range from journalists, to experts, to large media sites. "The New York Times" columnist Mike Isaac argued in 2019 that some of these companies see newsletters as a more stable means to maintain readers through a more direct connection with writers. In 2020, "The New Republic" noted an absence of local news newsletters, especially in contrast to the large number of national-level political newsletters. As of late 2020, large numbers of journalists and reporters were coming to the platform, driven in part by the long-term decline in traditional media (there were half as many newsroom jobs in 2019 as in 2004). Around that time, "The New Yorker" observed that while "Substack has advertised itself as a friendly home for journalism, [...] few of its newsletters publish original reporting; the majority offer personal writing, opinion pieces, research, and analysis." It described Substack's content moderation policy as "lightweight," with rules against "harassment, threats, spam, pornography, and calls for violence; moderation decisions are made by the founders."
In 2019, Substack added support for podcasts and discussion threads among newsletter subscribers.
Finance.
Authors can decide to make subscription to their newsletter free or paid, and to make specific posts publicly available to non-subscribers. , the minimum fee for a subscription was $5/month or $30/year, and Substack usually takes a 10 percent fee from subscription payments. Advertising to users plays no role in revenue generation. In February 2019, the platform began allowing creators to monetize podcasts. 
Substack reported 11,000 paid subscribers as of 2018, rising to 50,000 in 2019. In August 2020, Substack reported that over 100,000 users were paying for at least one newsletter.
Andreessen Horowitz provided $15.3 million in Series A funding in 2019, some of which went to bringing high-profile writers into Substack's network. Substack has provided some content creators with advances to start working on their platform. In 2019, the site provided a fellowship to some writers, which included a $3,000 stipend and a one-day workshop in San Francisco. In 2020, following the onset of the coronavirus pandemic, Substack extended grants of $1,000–$3,000 to over 40 writers to begin working on the platform. The decline of sports-oriented publications such as "Sports Illustrated", "Deadspin", and "SB Nation", coupled with the onset of coronavirus, led to a surge in sports journalists moving to write on Substack in 2019 and 2020. However, Substack competes with subscription site "The Athletic" in this submarket, so McKenzie says the company does not recruit as strongly in that market. 
The Substack founders reached out to a small pool of writers in 2017 to acquire their first creators. Bill Bishop was among the first to put his newsletter, "Sinocism," on Substack, providing his newsletter for $11 a month or $118 a year with daily content. As of 2019, Bishop's "Sinocism" was the top paid newsletter on the service. By late 2020, the conservative newsletter "The Dispatch" claimed the title of top Substack user, with more than 100,000 subscribers and over $2 million in first-year revenue, according to founder Steve Hayes. In May 2021, Substack acquired Brooklyn-based startup People & Company.
Leadership.
Substack was founded in 2017 by Chris Best, the co-founder of Kik Messenger; Jairaj Sethi, a developer; and Hamish McKenzie, a former "PandoDaily" tech reporter. Best and McKenzie describe Ben Thompson's "Stratechery," a subscription-based tech and media newsletter, as a major inspiration for their platform. Christopher Best operated as chief executive as of March 2019.
Competitors include TinyLetter, Lede, and the open-source Ghost.
Controversies.
Privacy incident.
On July 28, 2020, Substack sent out email notifications to all its users about changing privacy policies and notification about CCPA compliance. In this notification email, email addresses of all recipients were inadvertently included in the email 'cc' field rather than in the 'bcc' field. This exposed the email addresses of many Substack users. Per an acknowledgement post on the social media site Twitter, the company indicated that the issue was remedied after the initial batch of emails, but did not disclose the number of users affected.
Substack Pro.
In March 2021, Substack revealed that it had been experimenting with a revenue sharing program in which it paid advances for writers to create publications on its platform; this became a program known as Substack Pro. Substack has been criticized for not disclosing which writers were part of Substack Pro.