From Robert Sevin's Web Page:
There are two versions of Ackanomic in existence, due to a schism that occurred in Fall 1999. The schism was the result of a proposal that passed. Some of the players felt that the proposal's effects were invalid, and others felt they were valid. Those who felt the effects were valid formed Thin Acka, in which the proposal took effect. Those who felt the effects were invalid formed Fat Acka, in which the proposal did not take effect. Here are links to the home pages for each game:
Fat Acka is moribund at the moment so this page is about to redirect you to the Thin Acka page.