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 3,007,536 websites that are Facebook Signal Customers. We know of 1,717,432 live websites using Facebook Signal and an additional 1,290,104 sites that used Facebook Signal historically and 1,084,248 websites in the United States.
Get a list of 3,007,536 websites using Facebook Signal which includes location information, hosting data, contact details, 1,717,432 currently live websites and 1,290,104 sites that used this technology previously and 1,084,248 websites in the United States currently using Facebook Signal.