Apple has removed the Xgrid list from its list of publically maintained mailing lists.
The mailing list was described: "for user discussion use and deployment of Xgrid -- Apple's solution for parallel and distributed high performance computing".
Xgrid was trademarked in 2002, spawning rumors of its purpose. The mailing list attracted curious users during its brief existance, but no official discussion had begun, as Apple has not yet publicly announced Xgrid.