It may be necessary to indicate a time range by saying, for instance, Archaic through Hellenistic. Site sponsor may seem an odd category. In some cases, it will be simply the university where the server is. More complex relationships, however, may exist. For CDs, this is the publisher.
Audience is defined by the reviewer.
In general, we want to make it clear that sites or CDs are suited best for scholars, students, the general public or some combination of those groups. On occasion, it may appear that the site or CD has defined its audience in one way but the reviewer sees things differently. Should that occur, it should be noted here. Peer review is actually a more complex category, including availability and permanence. Along with each reviewer's name there should be both a physical and an email address.