MySims Kingdom - MySims Kingdom is based upon The Sims series but provides special and extremely different gameplay to the original series making it definitely worth your consideration.
Stardoll - Stardoll is an Amazing, Free-to-play Online Browser-based, Virtual World Simulation published by Stardoll AB, Mattias Miksche.
OurWorld - OurWorld is an Action, Great Online Virtual World, Social Interaction, MMO, and RPG Simulation by Flow Play.
InWorldz - InWorldz is an Amazing, MMORPG, Virtual World, and Social Networking Simulation.
YoWorld (Yoville) - YoWorld or formerly known as Yoville, is an Action, Browser-based, MMO, RPG, Single-player and Multiplayer, Social networking, and Virtual World Simulation developed by Big Viking Games.
Gaia Online - Gaia Online is 3D Social Networking, Virtual World, and Browser-based Simulation.