closegraph, the private warm-introduction graph

Field notes

The service builds an introduction graph from reciprocal email exchanges rather than message content. Its stated input is limited to four headers—sender, recipient, copied recipients, and date—and it excludes one-way mail, newsletters, subjects, bodies, and attachments. The page reports 4 members and 15,606 people indexed so far. Searches use first and last names; the site says addresses remain hidden and that members cannot browse one another’s contacts.