Interesting research into the centralization of Mastodon as an example of a decentralized social network. A few highlights:
Let’s Encrypt has been chosen as CA for more than 85% of the instances, likely because this service offers good automation and is free of cost.
Japan dominates in terms of the number of instances, users and toots. In total, it hosts 25.5% of all instances, closely followed by the US which hosts 21.4%.
…the top three ASes account for almost two thirds (62%) of all global users, with the largest one (Amazon) hosting more than 30% of all users— even though it only is used by 6% of instances. Cloudflare also plays a prominent role, with 31.7% of toots across 5.4% of instances.
Git is another decentralized network everyone has centralized. Github is just an instance of a git server, with lots of customizations for each of use. Yet, rather than devs hosting their own point-and-click git servers, like gitlab or gogs, the lazy solution wins.