Glossary
Fair use
A US doctrine permitting limited unlicensed use of copyrighted work, weighed case by case on factors including purpose and market effect. Whether AI training qualifies is being actively litigated, which is why many buyers prefer licensed data.
Courts weigh four factors — purpose and character of the use, nature of the work, amount taken, and market effect — with transformativeness and market harm dominating recent AI decisions. District courts in 2025 reached differing, fact-specific results on training, turning on how data was obtained and what the use did to markets for the originals. Appeals and further cases continue, so the boundary remains unsettled.
Why it matters
A licence removes the need to win a fact-specific fair-use argument after the fact.