RivenGuild.com was one of the first big Myst-related fan websites, launched by Gordon Currie in 1997. Doug McBride was also heavily involved at first, and later went on to join Cyan.
It featured news, the biggest discussion board at its time, a mailing list (RivenLyst, with The Lysts as its semi-successor), and various specialty sections, such as EDGE and GRID. A hosting service was announced and planned for mid-1999, but never launched.
At its peak, especially with a rush of newbies due to Myst III: Exile's release, the board reached about 3,500 members.
Starting in late 2000, it suffered from financial struggles, and eventually closed on June 1, 2001.
Various archiving efforts took place, but no single comprehensive result exists. Some pages can be accessed through the Wayback Machine. Since 2004, the domain has been effectively abandoned and turned into a placeholder page with ads unrelated to the original website.
The RivenGuild page also hosted a chat page, similiar to CyanChat. Abbreviated as RG or RG chat, it was used by many people who frequented CyanChat as well but was mostly a smaller, more close-knit group due to the lack of publicity compared to the Cyan-sponsored chat page. It was also used as a backup chatroom when Cho had a lock-in, or when CyanChat was overrun with trolls due to its being listed first on an internet search for "chat room".