# Plain Reckoner

> Free publisher measurement tools and research. Historical benchmarks, primary-source explanations and public datasets, with methods, dates and limitations.

This is an optional navigation index for compatible tools. Canonical HTML pages are authoritative. This file does not set crawler permissions, grant extra licences or guarantee search or AI inclusion.

## Start here
- [FAQ](https://plainreckoner.com/faq/): Static questions and answers about the tools, coverage and privacy.
- [Publisher tools](https://plainreckoner.com/app/): RPM, listing benchmarks, network checks and public-site inspection.
- [Data catalogue](https://plainreckoner.com/data/): Complete public CSVs, row definitions, methods and caveats.
- [Research findings](https://plainreckoner.com/notes/): Dated findings and source links.
- [About and authorship](https://plainreckoner.com/about/): What this project measures and how.

## Published data
- [What a thousand pageviews earned from ads, by subject, across 123 broker-checked businesses](https://plainreckoner.com/data/rpm-by-niche/): 123 published rows; One measured business: its niche, its RPM, and the months and traffic behind it.
- [Listing multiples by business model across 2,661 sold-status marketplace records](https://plainreckoner.com/data/sale-multiples-by-business-model/): 2661 published rows; One sold-status listing: recorded listing price, reported earnings and listing multiple.
- [Which AI crawlers 1,020 small ad-funded publishers name and block in robots.txt](https://plainreckoner.com/data/ai-crawler-policy-in-robots-txt/): 1020 published rows; One publisher’s robots.txt file: which AI crawlers it names, which it actually blocks, which names it carries that no vendor documents, and whose template it was written from.
- [Where a publisher’s ads.txt and their ad network’s own seller list disagree, across 462 checked relationships](https://plainreckoner.com/data/ads-txt-against-seller-lists/): 462 published rows; One relationship between a publisher and an advertising network: whether both files agree about it, and what the publisher’s own file looked like when it was read.
- [Combined public data JSON](https://plainreckoner.com/data/all-datasets.json): Original public rows and separate calculated views. Different units and potentially overlapping samples; do not add them into a unique-site count.

## Useful explanations
- [Traffic up, ad revenue down](https://plainreckoner.com/notes/traffic-up-ad-revenue-down/): A reproducible synthetic example and diagnostic steps, not observed network-performance data.
- [Session RPM versus page RPM](https://plainreckoner.com/notes/session-rpm-vs-page-rpm/): Keep denominators consistent.
- [Listing prices versus sale prices](https://plainreckoner.com/notes/listing-price-vs-sale-price-website-valuations/): Closing prices are not verified.

## Interpretation
Check each page's measurement date, evidence grade, sample and caveats before reuse. Historical, sale-selected observations are not a census or an earnings forecast. The instant question tool retrieves published excerpts and does not generate new evidence. Public data reuse is governed by the licence on each dataset page. Current crawler rules are at https://plainreckoner.com/robots.txt.