Professional organizations provide useful channels for communitating with specialists in history and other fields.
Directory of Historical Organizations in the United States
D. H. Hill Ref. E172 .D5
H-Net: Humanities and Social Sciences Online
This network, hosted at Michigan State University, seeks facilitate online communication among people with common interests in the study of history. Included are many listservs on specific topics in history, as well as online reviews of books and other media.
H-Net Discussion Networks
Discussion listservs that connect students, faculty, and researchers who seek to exchange ideas on topics in history. Note that H-HistMajor is a special list that focuses on topics of interest to undergraduate history majors.
The Official Museum Directory
D. H. Hill Ref. AM10 .A2 O4
American Library Directory
D. H. Hill Ref. Desk Z731 .A53