All of the sites listed here are free to browse, to set up a profile, and to communicate with others via message or email -- whether you initiate the contact or the other person does.
Date Hookup's criteria include hair and eye color, education, personality (shy or outgoing) and occupation.
It has social networking aspects such as a blog and an add a friend feature. OKCupid allows users to create an individual matching system in order to find the most compatible singles.
One advantage is that it's been around since 1997, long enough to have a base of over 5 million users, even though it is a lesser-known site.You can also view the site in Spanish or Portuguese, which may be helpful if you are bilingual.