In 1996, the idea arose to have a group called "Giga Society" for candidates scoring at or above the level of one in a billion on high-range intelligence tests, to encourage people to take the tests and collect data for norming and research. This was made known in personal correspondence, information included with score reports, and in articles in I.Q. society journals like OATH, In-Genius, and Thoth. Below is a non-exhaustive list of publications from the 1996-1999 period that mention the Giga Society as such; these serve as proof that the name "Giga Society" (or "The Giga Society") has been in use in the context (scope, namespace) of I.Q. societies since that time. Although the concept of the Giga Society originates in Paul Cooijmans, it has always been the intention to accept sufficiently high scores on tests by other constructors too, if those meet the society's stringent criteria.
After the second enrolment, in 1999, that member (Thomas Wolf) created a web site for the Giga Society, which existed until April 2004 at least. It had two guestbooks during its existence, and the entries of the second guestbook (2001-2004) have been saved and are provided on the present Giga Society web location. Darryl Miyaguchi's web site, Uncommonly difficult I.Q. tests, has mentioned the Giga Society since the late 1990s and referred to its subsequent web sites since 2000. Bill Bultas' web site puzz.com has likely mentioned the Giga Society in the late 1990s and early 2000s, but this can not be verified currently.
From early 2001 onward, Paul Cooijmans maintained a web page devoted to the Giga Society, which would later become gigasociety.com, and from 2003 or 2004 onward, Evangelos Katsioulis had a Giga Society web site for a number of years that existed alongside Paul Cooijmans' site.