Metric	Weight	Description
Top Provider User Share	30	Measures how many users are on the largest instance. Full points if <20%; 0 if >80%.
Top Provider Content Share	30	Measures how much content is hosted by the largest instance. Full points if <20%; 0 if >80%.
Ease of Self-Hosting: Server	20	Technical ease of running your own backend. Full points for simple setup with good docs.
Ease of Self-Hosting: User Interface	20	Availability and usability of clients. Full points for accessible, FOSS, multi-platform clients.

📋 Example Breakdown (Estimates)

Platform	Score	Visualization
📧 Email	95	🟩🟩🟩🟩🟩🟩🟩🟩🟩🟩🟩🟩🟩🟩🟩🟩🟩🟩🟩
🐹 Lemmy	79	🟩🟩🟩🟩🟩🟩🟩🟩🟩🟩🟩🟩🟩🟩🟩🟩
🐘 Mastodon	74	🟩🟩🟩🟩🟩🟩🟩🟩🟩🟩🟩🟩🟩🟩🟩
🟣 PeerTube	94	🟩🟩🟩🟩🟩🟩🟩🟩🟩🟩🟩🟩🟩🟩🟩🟩🟩🟩🟩
🖼 Pixelfed	42	🟧🟧🟧🟧🟧🟧🟧🟧
🔵 Bluesky	14	🟥🟥🟥
🟥 Reddit	3	🟥

📧 Email

Top Provider User Share: Google ≈ 17% → Score: 30/30
Top Provider Content Share: Google handles ≈ 17% of mail → Score: 30/30
Self-Hosting: Server: Easy (Can leverage hundreds of email hosting options) → Score: 16/20
Self-Hosting: Client: Easy (Thunderbird, K-9, etc.) → Score: 19/20

Total: 95/100

🐹 Lemmy

Top Provider User Share: lemmy.world ≈ 37% → Score: 21.5/30
Top Provider Content Share: lemmy.world hosts ≈ 37% content → Score: 21.5/30
Self-Hosting: Server: Easy (Docker, low resource) → Score: 18/20
Self-Hosting: Client: Good FOSS apps, web UI → Score: 18/20

Total: 79/100

🐘 Mastodon

Top Provider User Share: mastodon.social ≈ 40% → Score: 20/30
Top Provider Content Share: mastodon.social ≈ 45–50% content → Score: 20/30
Self-Hosting: Server: Docker setup, moderate difficulty → Score: 15/20
Self-Hosting: Client: Strong ecosystem (Tusky, web, etc.) → Score: 19/20

Total: 74/100

🟣 PeerTube

Top Provider User Share: wirtube.de ≈ 14% → Score: 30/30
Top Provider Content Share: Approximately 14% → Score: 30/30
Self-Hosting: Server: Docker, active community, moderate resources → Score: 16/20
Self-Hosting: Client: Web-first UI, FOSS, some mobile options → Score: 18/20

Total: 94/100

🖼 Pixelfed

Top Provider User Share: pixelfed.social ≈ 71% → Score: 4.5/30
Top Provider Content Share: Approximately 71% → Score: 4.5/30
Self-Hosting: Server: Laravel-based, Docker available, some config needed → Score: 15/20
Self-Hosting: Client: Web UI, FOSS, mobile apps in progress → Score: 18/20

Total: 42/100

🔵 Bluesky

Top Provider User Share: bsky.social ≈ 99% → Score: 0/30
Top Provider Content Share: Nearly all content on bsky.social → Score: 0/30
Self-Hosting: Server: PDS hosting possible but very niche and poorly documented → Score: 4/20
Self-Hosting: Client: Mostly official client; some 3rd party → Score: 10/20

Total: 14/100

🟠 Reddit

Top Provider User Share: Reddit hosts 100% of user accounts → Score: 0/30
Top Provider Content Share: Reddit hosts all user-generated content → Score: 0/30
Self-Hosting: Server: Not self-hostable (proprietary platform) → Score: 0/20
Self-Hosting: Client: Some unofficial clients available → Score: 3/20

Total: 3/100

How Scores are Calculated

🧑‍🤝‍🧑 How User/Content Share Scores Work

This measures how many users are on the largest provider (or instance).

No provider > 20%: If no provider has more than 20%, it gets full 30 points.
Between 20% and 80%: Anything in between is scored on a linear scale.
> 80%: If a provider has more than 80%, it gets 0 points.

📊 Formula:

Score = 30 × (1 - (TopProviderShare - 20) / 60)
…but only if TopProviderShare is between 20% and 80%.
If below 20%, full 30. If above 80%, zero.

📌 Example:

If one provider has 40% of all users:
→ Score = 30 × (1 - (40 - 20) / 60) = 30 × (1 - 0.43) = 17.1 points

🖥️ How Ease of Self-Hosting Scores Work

These scores measure how easy it is for individuals or communities to run their own servers or use clients.

This looks at how technically easy it is to run your own backend (e.g., email server, Mastodon server) or User Interface (e.g., web-interface or mobile-app)

Very Easy: One-command or setup wizard, great documentation → 18–20 points
Moderate: Docker or manual setup, some config, active community support → 13–17 points
Hard: Complex setup, needs regular updates or custom config, poor documentation → 6–12 points
Very Hard or Proprietary: Little to no self-hosting support, undocumented → 0–5 points

📚 Sources

📧 Email
W3Techs – Email Server Overview
🐹 Lemmy
Fedidb – Lemmy Software Stats
🐘 Mastodon
Fedidb – Mastodon Software Stats
🟣 PeerTube
Fedidb – PeerTube Software Stats
🖼 Pixelfed
Fedidb – Pixelfed Software Stats
🔵 Bluesky
SoftwareMill – Bluesky’s Decentralized Architecture
🟥 Reddit
Wikipedia - Reddit API Controversy

Footnotes

This is a work in progress and may contain mistakes. If you have ideas or suggestions for improvement, feel free to let me know.

Source: https://github.com/NoBadDays/decentralization-score/blob/main/decentralization_score_2025.04.md

top 19 comments

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[–] pcouy@lemmy.pierre-couy.fr 7 points 1 day ago (2 children)

There are a few things I don't like about this scoring system :

Why is there a "Top Provider Content Share" metric if its gonna score the same as the "Top Provider User Share" every time ?
Why is the Top Provider Content Share not higher than the user share ? For instance, emails usually have at least one sender and one recipient, making it twice as likely that at least one of them is using gmail. If an email has 10 recipients across 10 different providers, each provider has a copy of the data
Why is ease of hosting a mail server rated so well ? How is "leveraging email hosting services" decentralized in any way ?
Why are we using a random repo created a few hours ago by a random github user as a reference ?

[–] AnonomousWolf@lemm.ee 2 points 9 hours ago (1 children)

Why is there a "Top Provider Content Share" metric if its gonna score the same as the "Top Provider User Share" every time ?

As said in the footer, this is a work in progress, I'm posting it to get input and still refining sources

Why is the Top Provider Content Share not higher than the user share ? For instance, emails usually have at least one sender and one recipient, making it twice as likely that at least one of them is using gmail. If an email has 10 recipients across 10 different providers, each provider has a copy of the data

I'd love to get better data on this, I've looked but not yet found better data than what I included in the source

Why is ease of hosting a mail server rated so well ? How is "leveraging email hosting services" decentralized in any way ?

Here I'm a bit in two minds, sure it's difficult to SELF host email, but in practice it isn't because there are hundreds (Thousands?) of hosting options to choose from where you can choose your own domain etc. for the low price of basically-free

Why are we using a random repo created a few hours ago by a random github user as a reference ?

It's my repo, it's to keep track of the versions and so that others can copy, edit and share it if they like.

[–] dfyx@lemmy.helios42.de 2 points 9 hours ago (1 children)

Here I’m a bit in two minds, sure it’s difficult to SELF host email, but in practice it isn’t because there are hundreds (Thousands?) of hosting options to choose from where you can choose your own domain etc. for the low price of basically-free

I would prefer to limit this to actually hosting it on a machine you control. We don't consider redirecting a custom domain to a subreddit "self-hosting", do we? Yes, there are many email providers out there but that's more like existing lemmy or mastodon instances and not like hosting your own where you have full control over your data.

[–] AnonomousWolf@lemm.ee 1 points 9 hours ago

I would argue that is two different issues

"Are you free to easily move around and control your data" = High decentralization score

"do you have full control over your data?" = A different question

[–] dfyx@lemmy.helios42.de 2 points 11 hours ago

Why are we using a random repo created a few hours ago by a random github user as a reference ?

They aren't. That's the repo that has the latest version of the survey. The actual references are one section up.

[–] dfyx@lemmy.helios42.de 18 points 1 day ago (1 children)

Having set up a couple of mail servers myself, I wouldn't call it easy. Most solutions boil down to a tangled web of dovecot, postfix, ldap and amavis. There are preconfigured docker containers which make setup easier than a couple of years ago but if your use case is even just slightly different than the maintainers', you'll have to dive deep into a few dozen different config files. And of course, you'll have to find out how to configure SPF, DKIM and DMARC to have even a remote chance of your mails getting through to the big providers. I'd probably give email somewhere in the range of 8-12 points in that category.

Other than that, great summary!

[–] AnonomousWolf@lemm.ee 1 points 9 hours ago (1 children)

The scoring system is basically there to put a number on "How free are users and hosts of a platform to move around?" Or "How much power is in the hands of the people and not a few companies?"

For me Email scores very high in this regard.

As far as I know most Lemmy instances leverages paid-for or freemium services to have their instances work easily/properly

[–] dfyx@lemmy.helios42.de 1 points 8 hours ago* (last edited 8 hours ago) (1 children)

Then please update your category name to reflect that. Right now it says "Self-Hosting" which to the majority of readers means hosting it yourself, whatever the reason may be: privacy, configurability or just being safe from future enshittification.

As far as I know most Lemmy instances leverages paid-for or freemium services to have their instances work easily/properly

Yes but you can't compare a whole lemmy instance to an account on an email server that you share with others. The fair comparison would be hosting a lemmy instance to hosting your own email server and creating an account on Proton Mail to creating an account (or a community) on lemmy.world.

This looks at how technically easy it is to run your own backend (e.g., email server, Mastodon server)

Edit: also the description text "This looks at how technically easy it is to run your own backend (e.g., email server, Mastodon server)". Relying on Proton Mail or similar free services is not running your own backend.

[–] AnonomousWolf@lemm.ee 1 points 6 hours ago

You're right, thanks for the input. I'll make adjustments to take care of these flaws in the scoring system.

[–] Ulrich@feddit.org 6 points 1 day ago (2 children)

PeerTube Top Provider User Share: wirtube.de ≈ 14% → Score: 30/30

This is great. PeerTube has a flagship instance but it's not open registration. My only complaint is that I wish they were blacklist instead of whitelist by default.

Top Provider User Share: Google ≈ 17% → Score: 30/30

I sure as shit wouldn't have guess Gmail was only 17%. Do you have a source for this?

Bluesky Top Provider User Share: bsky.social ≈ 99% → Score: 0/30

Where's the other 1%?

[–] yessikg@lemmy.blahaj.zone 1 points 1 day ago

Is it counting Wafrn?

[–] AnonomousWolf@lemm.ee 1 points 1 day ago

Jip check the Email under the Sources section.

The best source I could find for Bluesky is also linked under sources, there aren't any real numbers but they explain that it's probably less than 1%

[–] morrowind@lemmy.ml 3 points 23 hours ago (1 children)

The fact that email is at the top here is clear evidence this is not a good metric dude. Email is not decentralized these days

[–] AnonomousWolf@lemm.ee 1 points 9 hours ago (1 children)

The scoreing system is basically there to put a number on "How free are users and hosts of a platform to move around?"

Or "How much power is in the hands of the people and not a few companies?"

For me Email scores very high in this regard.

[–] morrowind@lemmy.ml 1 points 2 hours ago

How much power is in the hands of the people and not a few companies?

That's exactly what I'm talking about though. Google, microsoft, and kinda yahoo basically control the entire market. A few providers like fastmail fight over fractions of percent. Email today feel much worse than lemmy

[–] supersquirrel@sopuli.xyz 8 points 1 day ago

This is amazing!

[–] lung@lemmy.world 3 points 1 day ago

Well...

If you follow the link to fedidb, refer to the "mau" monthly active users. Do some brief math and realize that lemmy.world accounts for about 50% of all active users

Email market share is harder, but many estimate that Gmail accounts for over 40%. Many many orgs use Google apps to make custom branded gmails with their own domains too

This is the typical "business power law" that states that the top player should control about 50%, the second player about 25%, etc. This is just kinda how the world works

[–] the_abecedarian@piefed.social 2 points 1 day ago (1 children)

Very cool! For the user scores, are you using monthly active users, total registered users, or something else?

[–] AnonomousWolf@lemm.ee 4 points 1 day ago

I used MAU where possible