The Sims Online brought Maxis' popular The Sims series into an MMO virtual world space. The game features the same basic concept as the offline version -- create your Sim, but and build a house and learn skills. However, where players of the offline Sims series found that their Sims could take care of many of their own needs if the resources were available, The Sims Online places these tasks into the hands of the player. The familiar list of needs that must be met included hunger, social, and hygiene. Putting your Sims to sleep, feeding them, and sending them to the shower were easy to take care of on your own, but social and fun skills involved other players. Each Sim could earn money and buy a lot for his or her own house or room with someone else. Houses owned by people online were open for visits.

Grouping was greatly encouraged through bonuses to skill learning. Learning skills was free, although not permanent. Without practice, skill levels would decline over time. If a group of Sims gathered to start reading cookbooks (one of the game's many skill objects), then everyone's skill in cooking would go up much faster than alone, and social needs were met this way. Sims could perform one of several jobs to earn money for land and other customization items. Jobs too, earned bonuses when completed together in groups.

Players also resorted to other forms of earning money, such as selling items and virtual shops. Eventually, EA worked with the community and added a custom item feature where users could create and sell things like furniture for profit.

In 2007, it was announced that after five years, The Sims Online would be folded into a larger online world called EA-Land in 2008. Shortly before this was set to happen, it was instead confirmed that the game would instead shut down entirely.