"To encrypt email in 1998 you’d run GnuPG from a terminal" In 1998, you'd probably run PGP. While GnuPG saw it's first 0.x releases from the end of 1997, 1.0

"To encrypt email in 1998 you’d run GnuPG from a terminal" In 1998, you'd probably run PGP. While GnuPG saw it's first 0.x releases from the end of 1997, 1.0 was only released in 1999 and commercial PGP was still very popular IIRC.