Aimed at children under 10, Togetherville creates an online "neighborhood" around each user. Parents can easily monitor the site and must approve all friend requests.
Recently relaunched with a tween focus, imbee has drawn 200,000 users since 2007. Popular features include streaming radio stations and video of kiddie celebrities.
Originally for girls but relaunched as gender neutral, Everloop allows users to create "loops" around their friends and interests, while parents get a security dashboard.
Talk about secure: launched in January, WhatsWhat.me has users log in using a webcam and facial-recognition technology, so hackers don't stand a chance.