Before it
Best practice mixed filtered web text with curated sources like books and Wikipedia.
The problem
Curated corpora are small and legally awkward; is the curation actually necessary?
What it introduced
Aggressive filtering and deduplication of web data alone, matching or beating models trained on curated mixes.
Why it matters
It reframed data quality as a filtering problem rather than a sourcing problem, which is how the field now treats it.
What modern models inherit
Web-only pretraining data with heavy filtering.
What came next
Dolma and FineWeb refined the same pipeline in the open.