A. A data sketch is a succinct summary of long data streams and serves as a more privacy-friendly way to represent data sets.
Sketches are widely used for processing extremely large volumes of data, and answering statistical queries about it. They help significantly reduce data processing times from days or hours to minutes or seconds.
Permutive uses data sketches in targeting (asking sketches if they contain a specific first-party user ID) and Insights (overlaying sketches to understand how datasets compare).
Sketches are especially privacy safe as they cannot be transformed back into their raw format, and reduce the amount of data we store at a given time.