Every trope page on this site shows some of the same numbers: demand signals, the share tagged underserved or novel, and registry titles. Here's what each one counts, and — more importantly — what it doesn't.
A demand signal is one specific thing a reader asked for or praised in a review, comment or post, picked out by Tropesmith's classifier. One review can give several. As of 21 October 2026 Tropesmith holds 2,725,785 of them: 95.7% come from Goodreads and Amazon reviews, 4.0% from BookTok comments and captions and 0.3% from Reddit posts. So most signals are readers praising or describing books they have read, not readers calling for a new book to be written. Found Family has 314,008, the most of any trope in the index (a signal that names several tropes counts toward each). That tells you the trope is talked about at scale — it says nothing about whether the specific angle you'd write is one of the ones readers want. Read the trope's page and its rejection data, not just the headline count.
Each signal gets a rarity tag (common, underserved or novel) from the text of that review or post alone; the classifier is never shown what is on the shelf. A tag points at where to look. It does not prove that no book answers the signal. 39% of all demand signals carry the underserved or novel tag; across the 442 tropes with at least 2,000 demand signals the share runs from 6% to 94%, which is why a trope's share is worth reading next to the corpus-wide 39%. The share is always the tagged signals divided by all signals for that trope. Use a high share as a reason to look harder at comp titles for the angles readers name; a low share means the classifier tagged fewer of the trope's signals that way.
Tropesmith also tags books, trope by trope, in a registry. A trope page shows how many registry titles carry it. The registry is deepest in romance, so a low number for a mystery or fantasy trope mostly means few titles have been tagged yet. It is a count of tagged titles, not of every book on the shelf.
Tropesmith reads reviews and posts some time after they are written, so the latest weeks are under-counted. Any change between two recent windows would measure that reading schedule rather than reader interest, so no page here claims a trope is rising or falling.
Use demand signals to find scale, the tagged share to decide what to check against comp titles, and the registry count only as a measure of tagging coverage — then read the rejection data on the trope page before you commit, because none of these numbers tells you whether you can execute the specific angle readers want.
One specific thing a reader asked for or praised in a review, comment or post, picked out by Tropesmith's classifier. One review can give several. As of 21 October 2026 Tropesmith holds 2,725,785 of them: 95.7% come from Goodreads and Amazon reviews, 4.0% from BookTok comments and captions and 0.3% from Reddit posts.
Tropesmith's classifier gives each demand signal a rarity tag (common, underserved or novel) from the text of that one review or post. It is never shown what is on the shelf, so the tag is a pointer to where to look, not proof that no book answers the signal. 39% of all demand signals carry the underserved or novel tag (21 October 2026).
Not by itself. Found Family has 314,008 demand signals, and 31,647 titles in Tropesmith's registry carry it — mentioned at scale, and many titles to compare against. The count tells you the trope is talked about; it doesn't tell you the angle you would write is open.
A Tropesmith Map scores your exact trope stack against demand and supply data — and shows where to look next.
Build my Map → See a real sample Map first →See it applied: Found Family, Cozy Mystery, the romance list.