VistA - join
Discussion pertaining to the use of the VistA healthcare information system (HIS) created by the US Department of Veterans Affairs (VA). Developed at taxpayer expense, VistA is in the public domain through the Freedom of Information Act (FOIA)
Low activity, 176 members, restricted

comp.lang.mumps - join
The M (MUMPS) language & technology, in general.
Low activity, 375 subscribers, Usenet

intersystems.public.cache - join
InterSystems Caché post-relational database.
Low activity, 1480 members, restricted