The WKT field contains a list of coordinates for each property that can be used to see a property’s boundaries on a map (like Google maps).
In contrast, a Shapefile would be a collection of properties, each with their associated data, which can be ingested into GIS software. Currently, we can only send CSV files of properties in our bulk exports. If the client requests boundaries we include the additional "boundaries.csv" table which includes the FIPS and APN for each property where we have boundary data. Within the boundaries file, the client can access the list of coordinates for each property via the WKT field (which means "well-known text representation of geometry"). Shapefiles would be a replacement for the delivery method of our properties (for example, we could send millions of properties via Shapefiles rather than CSV). We don't currently have the ability to perform Shapefile exports, but it’s something that we could explore given enough demand for it.