> ## Documentation Index
> Fetch the complete documentation index at: https://docs.cabinspress.com/llms.txt
> Use this file to discover all available pages before exploring further.

# ARC Signup Link & Attribution

> Generates copyable signup links with built-in attribution tracking.

## Who this is for

Authors promoting an ARC team across social channels and tracking which channels work.

## Overview

Generates copyable signup links with built-in attribution tracking.

## How it works

### Copy link modal includes

* A **short link** copied by default (`cabinspress.com/go/{code}` or `{custom-domain}/{code}` when configured)
* **Attribution source dropdown** with 19 presets:
  * Instagram, Facebook, Pinterest, Goodreads, Threads, Discord, TikTok, X, Bluesky, YouTube, Reddit, Substack, BookBub, Newsletter, LinkedIn, Mastodon, Tumblr, Snapchat, Email
  * Plus a **Custom...** option for anything else
* Author copies the link with the source baked in and shares it
* Each signup is tagged with the source
* **Click count** shown after copy; increments when readers follow the short link
* **Copy full URL** available as an advanced fallback when a platform strips UTM parameters

### Configuration on the book

* **Signup window** — start and end dates when the form accepts new readers
* **Download window** — separate start/end dates when readers can actually download the file
* **Max ARC readers** — optional cap (signups beyond this return "ARC signup is full"); leave blank for unlimited

### Attribution reporting

* **Attribution pie chart** on the book detail page shows signup count by source
* First-touch attribution (the source from the link they used to sign up)
* Missing sources show as "unknown"

## Common questions

* When the cap is hit, the signup form returns a clear error message — no waitlist today
* Signup form remains accessible after cap (returns error rather than 404)
* Multiple signup windows per book are not supported — one window per book at a time

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## Next steps

[**ARC Theme and Branding**](/arc/arc-theme-and-branding)