UGC

UGC (or "user-generated content") is content that is created by users of a platform, rather than by the platform itself. It's often used in the context of discussing SEO (search engine optimization) and content marketing; from Buttondown's perspective, author's emails and comments from subscribers are UGC.

Back in 2019, Google recommended platforms (such as Buttondown) to start marking links as UGC to help them understand the semantic meaning of their content.

This means some of your links might have a bit of extra markup around them, like this:

<a href="https://example.com" rel="ugc">
  Here's a link to my favorite website.
</a>