Two Lustre community groups exist. Whamcloud participates in activities with both groups. Details of their activities can be found at their respective websites - EOFS and OpenSFS.
OpenSFS and HPCFS announced at LUG 2011 that they were joining forces into a single organization, and will be working closely with EOFS to coordinate their efforts.
Four community lists are available on http://lists.lustre.org/mailman/listinfo
The list pages, including archives are open to the public:
Lustre has a chat room on ~rhenwood:freenode.org. #lustre. Drop by and say hi!