NetNewsWire is a feed reader. Blogs publish feeds and you can subscribe to get updates aggregated for you.
From 2005–2013, I subscribed to dozens of blogs and read most of it. It was the golden age of the web. When Google killed Reader in 2013, I lost track of many blogs and Twitter took over with more direct communication between web developers.
In 2021, I started using a feed reader again because of woodworking. Woodworkers aren’t very active on Twitter, but some blog frequently.