It's a really interesting new (emerged in the last few years) piece of technology.

It's kind of a cross between SQLite and columnar analytical databases such as Snowflake or Cassandra.

You can run it happily on a laptop, but because it's column oriented it can calculate aggregates (group by/count queries for example) incredibly fast - so it's better for a lot of analytical workloads than regular row-oriented databases.

I have some initial notes from trying it out here: https://til.simonwillison.net/duckdb/parquet