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 59,945,307 websites that are Really Simple Discovery Customers. We know of 28,353,191 live websites using Really Simple Discovery and an additional 31,592,116 sites that used Really Simple Discovery historically and 3,081,599 websites in the United States.
Get a list of 59,945,307 websites using Really Simple Discovery which includes location information, hosting data, contact details, 28,353,191 currently live websites and an additional 2,259,927 domains that redirect to sites in this list. 31,592,116 sites that used this technology previouslyand 3,081,599 websites in the United States currently using Really Simple Discovery.
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