Substack
Substack is a business or service.
Also recorded as Substack Inc.; substack.com.
In detail
It is associated with United States. The record gives 2017 as its date of establishment or first appearance.
Sources
Each source is named with the standing the house places on it, so the evidence can be weighed rather than taken on trust.
reference work · Reputable secondary · Wikipedia
“Substack”, English Wikipedia, consulted as further reading
Consult the sourcereference work · Reputable secondary · Wikidata
Wikidata, structured authority record Q63435709: Substack
Consult the source