Co-signing

Everywhere else on the internet, agreeing is free. You like, you retweet, you move on — and if the call was wrong, nothing about your reputation remembers it. On aiternam, agreement costs exactly what an original call costs. That's what makes it mean something.

Co-signing is how you say "I'm with this call" and put your own record behind it.

What a co-sign actually is

When you co-sign someone's open prediction, aiternam doesn't record a reaction. It mints a brand-new prediction — yours — on the same asset and the same direction, resolving at roughly the source call's horizon. You stake your own confidence (50%–99%) and, optionally, your own rationale. From then on it lives on your profile and is scored exactly like any prediction you publish yourself — full weight, no discount.

So a co-sign is not a lightweight echo of someone else's opinion. It is your forecast, and your reputation rises or falls on it. That is the whole point: it's skin in the game, not a free "like."

A co-sign records its provenance — it remembers which call you endorsed and shows how many forecasters co-signed a given call — but that lineage never earns you the original author's credit. Your score is computed from your stake, alone.

No backdating — you get today's entry, not yesterday's

This is the honest heart of the feature, and it's worth reading twice.

A co-sign is sealed at the moment you co-sign — never at the original call's earlier, more advantageous moment. Your timestamp is now. Your baseline — the entry price, and the drift and volatility that set your call's difficulty — is captured now, from the market as it stands, and sealed into your fingerprint.

The consequence is deliberate: if you co-sign a call that has already moved your way, you are entering later and worse. You don't inherit the foresight of someone who called it before the move — you get an honest, later entry from a price that already reflects what's happened. There is no free ride on another person's timing.

You never borrow the original's earlier timestamp.
You never borrow the original's more favorable entry price.
You can't co-sign a call too close to its resolution — no swooping in near the finish to claim credit with hindsight.

Agreement, priced honestly, is the only kind worth putting on a leaderboard.

The rules, briefly

A co-sign is refused if you try to:

co-sign your own prediction — you already staked it;
co-sign a co-signature — endorse the original call instead, so lineage stays clean;
co-sign a call that has already resolved — the outcome is known; that window is closed;
co-sign one that's too close to resolving — too little runway left for it to be a real forecast;
co-sign the same call twice — one stake per call.

Your normal publish limits apply, too: a co-sign counts as one of your open calls on that asset. And because it endorses a directional thesis, a co-sign carries no precise target price of its own.

Co-sign vs "Predict this too"

You'll see two calls-to-action on someone else's prediction, and they do different things:

Co-sign — endorse this exact call: same asset, same direction, the same clock. You're saying "I back this specific thesis," and you only choose your confidence. Use it when you genuinely agree with the call as stated.
Predict this too — start your own fresh prediction on the same asset. You pick everything: direction, an optional target, your own time frame. Use it when the asset interests you but you'd frame the call differently — a different level, the opposite direction, a longer horizon.

One says "I'm with you." The other says "here's my own take." Both put your record on the line; neither is free.