Some Dianics are feminist Witches, both lesbian and heterosexual, who often come to the Craft through feminism. Although these women may be involved with men in one way or another, they agree that religion has over-emphasized the male for the last several thousand years, and therefore want to share their women's energy in women's circles. They may or may not also be involved with the mainstream pagan community, and they may or may not participate in magic and ritual with men.
The most visible groups of Dianics are those who are lesbian Dianics. They are generally not interested in revering any sort of male deity or in working with men in circle. They choose to limit their dependence on and acceptance of the male-defined world as much as possible, and they do so not to exclude men but rather to celebrate women and the feminine. For that reason many of them do not interact much with the "mainstream" pagan community.
(There are also those who call themselves Dianic and who are not like those described above, but who practice Witchcraft based on the traditions found books like those of anthropologist Margaret Murray. However, the term is more often meant to designate those practitioners described in the first two paragraphs.)