Heterogeneous

This is not the "ONE-OF-US.NET" network; it isn't married to the Nerd'ster, and it certainly is not MY network.
The signed content does not have to meet any particular format and doesn't need to be communicated using any specific API.

The paradigm is simple: Use your own crypto key and authentically state and publish stuff on your own. (There is no technology, formats, or APIs... just 2 open source demos)

The cryptography used by our apps is stock and open source; other services could use any key types they choose.
Being heterogeneous enables competition and evolution. Your Spotify likes could make my Pandora station better.
The statements one-of-us.net and nerdster.org use are not by any means the only statements allowed. You can sign whatever you want. Other services might encourage statements of the form I recognize, I lothe, I appreciate, etc...
Find everything from people you choose to follow People use their identity key to sign and publish their delegates, and so any service can find those by starting there. If someone you admire doesn't necessarily Facepost where you may be connected, you can still find their contributions elsewhere (eg. NYT comments, Reddit posts)

The Simpsons Bot Farm Demo on the Nerdster published signed statements by "Bart@nerdster.org", "Homer@nerdster.org", among others. Nothing prevents "Bart@x.com", "Homer@truthsocial.com", "Milhouse@discord.com", etc... (Note that these names were not chosen by those actors as their usernames but rather they were identified (vouched for, trusted) by your network from your PoV. You would see the same names across all platforms.

Nerdster and ONE-OF-US Statement Publishing

Both apps publish all signed statements at https://export.<domain>?spec=<key token>
Services can compute this link, and you can get it directly on the Nerdster by right clicking on a person or key in the network tree pane and choosing "statements"
Serices can compute a key's token by computing the SHA1 has of its JSON string.
The Nerdster has this functionality diplayed for demo at "/etc" => "Validate...." menu, or you can get it directly by double tapping on any key.
(Make sure to choose Show for "JSON, keys, and statements" in the Settings menu.)

Example - my signed, published, Nerdster statements:

My Nerdster key:

{

"crv": "Ed25519",

"kty": "OKP",

"x": "qmNE2eAuBYKAdtOJrwq9bpeps-HDsvV9mRhWT1R8xCI"

}

My Nerdster key's token:

f4e45451dd663b6c9caf90276e366f57e573841b

The embedded pane on the right can be used to compute my key's token. (It's not verifying a signature in this case, and so don't expect to see anything about a invalid or invalid signature.)

My Nerdster statements: https://export.nerdster.org/?spec=f4e45451dd663b6c9caf90276e366f57e573841b

Sign in is ready now

Notice how the Nerd'ster's QR sign in code tells the phone app.

What domain the service claims to be (nerdster.org)
Where and how to communicate the identity public key and the delegate public/private key.
From the JSON text below the QR code:
- domain: "nerdster.org"
- method: "POST"
- rui: "https://signin.nerdster.org/signin"

Any service can do this right now, right away:

Have us identify ourselves using the existing ONE-OF-US.NET phone app.
Have us create and use our own delegate keys (created and managed specifically for and publicly associated with their service) so that we act as ourselves on their service and be recognized across all services.
Leverage our network.

(In case your click dismissed the sign in QR code, click "Sign in" to see it again.)

Opt-in

The Nerd'ster is purist in that everything is signed an open.

Other services aren't expectded to go this far. If Airbnb, for example, wanted to adopt this, to leverage your reputation, they would still need private data (eg. your payment information). Additionally, they could double sign reviews: one signature by your delegate (to confirm that your reputation stands behind the review) and one by theirs (to confirm that the stay actually took place).