Journalists use Signal to surface relevant trends, photos, videos and posts from Facebook and Instagram for use in their storytelling and reporting.
https://www.facebook.com/facebookmedia/get-started/signal
Analytics and Tracking
Get access to data on 4,736,990 websites that are Facebook Signal Customers. We know of 1,384,773 live websites using Facebook Signal and an additional 3,352,217 sites that used Facebook Signal historically and 755,688 websites in the United States.
Get a list of 4,736,990 websites using Facebook Signal which includes location information, hosting data, contact details, 1,384,773 currently live websites and an additional 3,226,547 domains that redirect to sites in this list. 3,352,217 sites that used this technology previously and 755,688 websites in the United States currently using Facebook Signal.