Really Simple Discovery is a way to help client software find the services needed to read, edit, or "work with" weblogging software.
https://cyber.law.harvard.edu/blogs/gems/tech/rsd.html
Syndication Techniques
Get access to data on 60,191,111 websites that are Really Simple Discovery Customers. We know of 28,080,652 live websites using Really Simple Discovery and an additional 32,110,459 sites that used Really Simple Discovery historically and 3,055,663 websites in the United States.
Get a list of 60,191,111 websites using Really Simple Discovery which includes location information, hosting data, contact details, 28,080,652 currently live websites and an additional 2,148,742 domains that redirect to sites in this list. 32,110,459 sites that used this technology previouslyand 3,055,663 websites in the United States currently using Really Simple Discovery.
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