Cross-Posting to Medium and Substack: Does It Hurt SEO?

My Medium friends can read this over on Medium.

I publish almost everything twice. Medium first, Substack a bit later. Same text, two domains.

And I bet every SEO guide you've seen out there warns about duplicate content. Google gets confused, the two versions compete, both lose. That's the theory, at least. And it's a logical one.

So I looked at my own data. Google Search Console, both domains, 90 days.

Setup

My Medium runs on stories.byburk.net, my Substack on letters.byburk.net. Both custom domains, both in Search Console. I pulled the top 1,000 search queries for each, over 90 days, in August.

In that window Medium got about 4,200 clicks from 380,000 impressions. Substack got about 700 clicks from 290,000 impressions.

So Substack shows up a lot. It just gets clicked a lot less.

Overlap

Out of roughly 1,000 queries per domain, only 83 show up on both.

That's about 8 percent overlap in the GSC.

The rest of the time, the two domains rank for different things. Same articles, mostly. But different searches. I guess Google already sorts a lot of that out on its own. Which is super interesting to me.

One winner

When both versions do rank for the same query, Google usually picks one and pushes the other way down. No penalty. The copy just sits somewhere on page four or five.

A few examples:

• "substack vs medium": Medium on position 10, Substack on 44
• "medium seo": Medium 7, Substack 36
• "payhip vs gumroad": Medium 7, Substack 41

Medium wins most of those. But not all. For "best blogging platform" Substack took position 8, Medium 11.

Which one Google picks is hard to predict. So every cross-post gives me two chances instead of one.

Page one twice

And sometimes Google doesn't pick at all.

26 of those 83 shared queries have both versions on page one. "claude cowork vs antigravity", for example: Medium on position 2, Substack on 10.

That's twice the space on the results page. For the same piece.

Downsides, of course

Substack doesn't let you point a canonical tag at the Medium original. So you can't tell Google which version came first. Google decides. On Medium, however, you can do that. But since my Medium stories usually rank better, I stopped adding canonical links to my Substack version.

It hasn't hurt so far.

But Google doesn't always decide well. In September I checked my ten newest Medium stories with Search Console's URL inspection. Five were "unknown to Google". Two were marked as duplicates, with Google's canonical pointing at other people's Medium posts. Not my Substack. Strangers. That's obviously not the way I want it.

This might be a Medium problem, not a cross-posting problem. I will look into that further.

Also: this is one writer, one niche, 90 days. Your numbers might look totally different. And my data is from August. I will update this as I find new metrics or issues.

What I do

I keep cross-posting. Medium first, then Substack.

One small change: I vary the title and subtitle a bit per platform, sometimes. Different enough that Google is less likely to filter one version out completely. Also the audience is different.

Other than that, my strategy stays the same.

If you're not already, follow me on Medium.

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