Are we decentralized yet?

Neat! I'm not surprised at the findings here. BlueSky (for the average user) is pretty much a drop in replacement for Twitter.

Despite the smaller total numbers in Mastadon, it's great to see that the ecosystem seems to be successfully avoiding centralization like we've seen in the AT-Proto ecosystem.

I suspect that the cost of running AT proto servers/relays is prohibitive for smaller players compared to a Mastadon server selectively syndicating with a few peers, but I say this with only a vague understanding of the internals of both of these ecosystems.

Running a PDS server for yourself and a few friends is not very expensive afaik, but there's also not much benefit to doing so, because the point of the PDS is to have a clean separation between your own data and the rest of the network.

The expensive things in ATProto are the Relay (crawls/listens to PDSs to produce the firehose) and the AppView (keeps a DB of all posts/likes/etc to serve users' requests). Expensive at scale anyway; if you want your own small network for hosting non-Bluesky posts (like WhiteWind's longer character limit), the event volume will be manageable.

For a lot of stuff though ATProto is built in a way that you shouldn't have to host your own; you can implement your own algorithmic feed that reads from the Bluesky Relay's firehose, or your own frontend that still gets data from the Bluesky AppView.

Running a relay is not expensive anymore (it used to be), with recent changes it's about $30/mo. Running an AppView that ingests all ongoing Bluesky traffic (and puts it into database) is more expensive ($300/mo currently) but if you were happy with a partial view of the network, you could get it down by a lot.

I thought only the way to avoiding the full firehose was connecting to Bluesky's centralized Jetstream instances, and that if anyone else wanted to host Jetstream without depending on Bluesky infra other than the PDS, they would still need to pay the full price for the firehose bandwidth and storage.

I'd be happy to be wrong here though.