From John Esposito @ Middle East Online:
Like the status of women in all the World's religions, in Islam and Muslim societies patriarchy played and in many cases continues to influence the status and roles of women. The place of women in the formative period of Islam reflected Qur'anic concerns for the status and rights of women as well as the patriarchal structure of the societies in which Islamic law was developed and elaborated. The status of women and the family in Islamic law was the product of Arab culture, Qur'anic reforms, and foreign ideas and values assimilated from conquered peoples. While the Qur'an introduced substantial reforms, providing new regulations and modifying local custom and practice, at the same time, much of the traditional pre-Islamic social structure with its extended family, the paramount position of males, the roles and responsibilities of its members, and family values was incorporated.
A new source of women's empowerment today has become active participation in the mosque and use of Islam's tradition to reclaim their rights in Islam. Reformers today emphasize that just as women during the time of the Prophet prayed in the mosque, so too today they actively exercise that right. In the centuries after the death of Muhammad, women played a small but significant role as transmitters of hadith (prophetic traditions) and in the development of Sufism (Islamic mysticism).