Listing Sync is the only listing product that we are able to share a list of the number of sites syncing to (30+ sources). Listing Sync is more of an "instant" solution with direct results on those listing sources displayed in the dashboard.
Listing Distribution, which is included with Listing Sync Premium subscriptions, is meant to be the ultimate citation builder, however we do not have access to up-to-date lists or the exact number of sources Listing Distribution can reach for any particular business vertical. This is because: 1) the data providers are constantly growing and changing their reach and we are only connecting directly with them, and 2) the data drovider sources are proprietary information belonging to each data provider.
We submit weekly to the major data providers ("Data Aggregators") who provide business information to 300+ directories. It's up to each directory whether or not to publish listings. Some directories are limited to certain types of business verticals (e.g., Judy's Book, Healthgrades, ZocDoc, Avvo, UrbanSpoon, etc.).
How does Listing Distribution work?
How long does Listing Distribution take?
Listing Sync vs Listing Sync Premium