The network graph analysis indicates that the fellowship of the dossier is a close-knit group; everyone knew each other long before embarking on the quest to find the alleged Russian collusion. All of the project key players are related through marriage, family relations, or work affiliations.
Sidney Blumenthal’s network is noteworthy because his email address book contains many of the dossier characters including Jacoby, Simpson, Winer, and others.
A sampling of Blumenthal’s first 20 contacts (out of over 4000) shows an over 96% linkage to anti-Trump publications, most of these are from mainstream media sources.
So who researched and wrote the core parts of the dossier? It looks like it was a team effort. Most of the textual evidence points to Glenn Simpson and his wife Mary Jacoby as the architects of the dossier framework.
The bottom line:
Simpson and Steele did far more than simply conduct sordid opposition research for the Clinton campaign. By various machinations, they successfully reached the most influential people in UK and US politics, the media, and federal government agencies and shaped/influenced the narrative of the 2016 presidential elections. There is little doubt that Simpson/Jacoby and their US political/media network and Steele with his enablers in Hakluyt, the British media, and the Foreign Office successfully waged a full-scale influence operation against the US and are continuing to do so even now.
Read very lengthy analysis including examples of OSINT tools.