[updated 30 January 2013/chaz]
The purposes of the WSFS, according to its rules, are as follows: to choose the recipients of the annual Hugo Awards (Science Fiction Achievement Awards), to choose the locations and Committees for the annual World Science Fiction Conventions (the Worldcons), to attend those Worldcons, and to choose the locations and Committees for the occasional North American Science Fiction Conventions (the NASFiCs). (A NASFiC is held in North America in any year when the Worldcon is outside of North America.)
Almost all of the activities of the Society are performed by the selected convention committees, which are independent groups. Membership in the Society is defined as all those for whom membership dues have been paid to the current Worldcon committee. The convention committees are selected two years in advance and you may wish to contact them as listed above for further information.
You can send mail to all upcoming Worldcons and some number of past Worldcons by emailing <email@example.com> but in most cases you should send mail to the specific Worldcon of interest to you as listed above or below.
WSFS is an unincorporated non-profit organization governed by a Constitution and Standing Rules as documented at <http://wsfs.org/bm/rules.html>.
Note to Web surfers looking for WSFA, the Washington Science Fiction Association. You've found WSFS, the unincorporated literary society that sponsors the annual World Science Fiction Convention. WSFA can be found at <http://www.wsfa.org>.
"World Science Fiction Society", "WSFS", "World Science Fiction Convention", "Worldcon", "NASFiC", "Hugo Award", and the distinctive design of the Hugo Award Rocket are service marks of the World Science Fiction Society, an unincorporated literary society. You can contact the WSFS Mark Protection Committee at <firstname.lastname@example.org>.