For years, Substack was easy to categorize: a newsletter platform where independent writers built paid audiences.
But now, that description no longer fits.
Today, Substack is evolving into something much larger: a creator-led media ecosystem spanning long-form articles, podcasts, video, live conversations, and social-style posts. More importantly for marketers, it's beginning to open the door to brand partnerships in ways that feel fundamentally different from traditional social advertising.
It's still early, but that's exactly why it's worth paying attention.
Quick Answer: Should Brands Pay Attention to Substack?
Yes. While Substack is still early as a marketing channel, it has become one of the most promising emerging creator platforms for brands targeting affluent, highly engaged audiences. Unlike traditional social networks, Substack combines long-form content, direct subscriber relationships, and premium creator communities. As the platform expands brand partnerships beyond newsletters into podcasts, video, live events, and sponsored creator collaborations, marketers should begin evaluating where it fits within their creator and content strategies.
What Is Substack?
Substack is a creator publishing platform that allows writers, journalists, analysts, podcasters, and other creators to build direct relationships with audiences through subscriptions. Originally known for newsletters, the platform now supports articles, podcasts, video, Notes, and live conversations, making it a broader creator media ecosystem rather than simply an email platform.
While Substack doesn't yet offer a mature self-service advertising platform, its evolving approach to Substack marketing and Substack advertising centers around creator partnerships rather than traditional display ads.
Substack Has Moved Beyond Newsletters
Substack has spent the last several years expanding beyond email publishing into a destination where audiences consume content directly within the platform.
Creators can now publish:
- Long-form articles
- Podcasts
- Video
- Short-form "Notes" (similar to X)
- Live conversations and community discussions
The result is a platform designed around depth instead of endless scrolling, and that shift appears to be resonating with users.
Substack reports tens of millions of weekly readers and listeners, more than 100,000 monetizing publishers, and over 5 million paid subscriptions globally. The app is also widely available across iOS and Android and currently ranks among the top news apps in Apple's App Store.
Solid numbers, but perhaps more telling is its audience growth.
U.S. unique visitors grew from just 4.9 million in April 2023 to a peak of 15.5 million by October 2025, reflecting the platform's rapid evolution from a niche publishing tool into a mainstream content destination.
The Audience Looks Different Than Traditional Social
Most social platforms are fighting for younger users and shorter attention spans. Substack is attracting something else entirely. Current audience data suggests the platform skews:
- Affluent
- Slightly female
- Older than traditional social platforms
More than 60% of visitors report household incomes above $100,000, with the strongest reach among audiences aged 45 and older.
For many premium, luxury, financial, travel, healthcare, and B2B brands, that's an audience profile that's increasingly difficult to reach through traditional creator channels alone.
Community May Be the Real Product
Audience demographics are only part of the story. Substack's biggest differentiator may be the relationship creators build with their subscribers.
Unlike algorithm-driven feeds, Substack revolves around intentional subscriptions. Readers choose who they want to hear from and often engage with creators across newsletters, comments, podcasts, live discussions, and Notes. That creates a different type of loyalty.
Research from The Verge found that 37% of Substack users feel connected to and part of a larger conversation. That's higher than YouTube (34%) and TikTok (30%), reinforcing the platform's reputation as a highly engaged, community-driven environment.
For brands, that kind of trust can be difficult (and expensive!) to build elsewhere.
Why Substack Could Matter for AI Search
There's another reason marketers should keep an eye on Substack, and it has little to do with newsletters.
As AI-powered search experiences continue to evolve, they're placing greater emphasis on high-quality, authoritative content that directly answers users' questions. Public Substack posts are crawlable, meaning they have the potential to appear in AI-powered search experiences such as Google AI Overviews, ChatGPT Search, and Perplexity when they're relevant and considered authoritative.
While Substack has not announced formal partnerships with Google or major LLM providers, its publishing model aligns well with the types of content these systems increasingly surface: expert-driven analysis, original insights, and in-depth explanations rather than short-form social posts.
For brands and creators already investing in thought leadership, that opens an interesting opportunity. A well-written Substack article doesn't just reach newsletter subscribers. It also has the potential to contribute to long-term discoverability across both traditional search engines and AI-generated search results.
We're already seeing PR and SEO experts discuss Substack as an extension of earned media. Instead of thinking about it solely as a distribution channel, brands may want to view it as another place to publish authoritative content that can continue working long after it's sent to subscribers.
Brand Partnerships Are Starting to Arrive
Historically, Substack generated revenue primarily through creator subscriptions. But now the company appears to be expanding its commercial strategy.
Rather than launching a traditional advertising platform, Substack has begun piloting sponsorship opportunities that connect brands directly with creators. These partnerships can extend beyond newsletter sponsorships into formats such as:
- Podcasts
- Video
- Live events
- Subscriber-exclusive experiences
- Multi-format creator collaborations
The approach feels much closer to creator partnerships than conventional digital advertising, allowing brands to participate within trusted editorial communities instead of interrupting them.
Several well-known brands have already participated in the platform's initial sponsorship pilot, signaling meaningful interest from advertisers even before a broader rollout.
It's Early, But That's What Makes It Interesting
The sponsorship program remains in its pilot phase, and many details have yet to be announced publicly. Questions around measurement, audience targeting, reporting, eligibility, and partnership formats are still evolving.
That's not unusual.
Many of today's most valuable advertising channels looked incomplete during their earliest commercial launches. The brands that benefited most were often the ones paying attention before the platform reached full maturity.
Substack appears to be following a similar trajectory.
The Code3 Take
Not every emerging platform deserves marketers' attention. Depending on your brand, category and goals, Substack might.
It combines several characteristics that are becoming increasingly rare in today's digital ecosystem:
- Highly engaged communities
- Long-form attention
- Affluent audiences
- Strong creator trust
- Premium editorial environments
For brands that rely on education, expertise, storytelling, or considered purchasing decisions, those ingredients are compelling. As AI-powered search continues rewarding authoritative, long-form content, platforms like Substack may also play an increasingly important role in helping brands build visibility beyond traditional social channels.
We're still in the early chapters of Substack's commercial story, and there's plenty left to learn as the platform expands its partnership offerings. But if current growth trends continue, it has the potential to become a meaningful addition to the creator marketing landscape.
It's not another social network. It may be something more valuable: a place where audiences choose to spend time with creators they genuinely trust, and where brands can become part of that conversation in a way that feels additive rather than interruptive.