Substack is a blog because it is a website that publishes content on a regular basis. The website has articles that are written by different authors, and the website also has blog posts that are written by the same author. The website also has an RSS feed that allows users to subscribe to the website’s latest content. Additionally, the website has a blog section that is specifically for the publication of blog posts.
Lastly, the website also has an “about” page that provides information about the website and its authors. Overall, Substack is a website that publishes content on a regular basis, and it is classified as a blog because it has a blog section and an RSS feed.