A decade or so ago, people started realizing that every single idea on the internet has been done before. What started was a trend towards hyper-niching. Nowadays, you can find very specific blogs on Labrador Training raking in 200,000 monthly users, but if you'd start a "Dog Training" site today, you would never get to that point.

Bundling reacts to differentiated desires by creating a less differentiated publication that’s fairly valuable to everyone. But as the cost of the reader’s time rises, focus pays off. And the subscription newsletter model makes it easier than it’s ever been to profitably focus on exactly one topic, and build a one-person monopoly.