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 4,582,952 websites that are Facebook Signal Customers. We know of 1,443,549 live websites using Facebook Signal and an additional 3,139,403 sites that used Facebook Signal historically and 806,644 websites in the United States.
Get a list of 4,582,952 websites using Facebook Signal which includes location information, hosting data, contact details, 1,443,549 currently live websites and an additional 3,595,383 domains that redirect to sites in this list. 3,139,403 sites that used this technology previously and 806,644 websites in the United States currently using Facebook Signal.