What is social infrastructure?
Eric Klinenberg has popularized this term, which is defined in his book, "Palaces for the People", and defined, among other ways, as "Public institutions, such as libraries, schools, playgrounds, and athletic fields, are vital parts of the social infrastructure. So too are community gardens and other green spaces that invite people into the public realm. Nonprofit organizations, including churches and civic associations, act as social infrastructure when they have an established physical space where people can assemble, as do regularly scheduled markets for food, clothing, and other consumer goods." 
What is an amenity?
From an economic or housing market perspective, an amenity is, according to Jeffrey Lin, "a feature of a neighborhood that some household is willing to pay for in order to enjoy—for example, a good school, a view of the ocean, or a wide variety of restaurants all increase the amenity value of a neighborhood. Households’ demand for a neighborhood amenity may depend in part on economywide factors." 
Amenities data sources
OpenStreetMap, a free database of places in the world
Get more details about amenities data on our Sources page.
- Eric Klininberg. "Palaces for the People: How Social Infrastructure Can Help Fight Inequality, Polarization, and the Decline of Civic Life". Shop your local indie bookstore
- Jeffrey Lin. "Understanding Gentrification's Causes: What do three centuries of Philadelphia history tell us about today’s changing neighborhoods?". 2017. Federal Reserve Bank of Philadelphia Research Department. PDF.