More than likely, you have heard of the game The Sims. Onverse may not offer quite as many features as The Sims. But for a free alternative, the game is excellent. Upon playing Onverse, you will be able to interact with other real Onverse players, using the game's advanced social networking capabilities. Onverse starts out by requiring you to setup a profile. From there, your character (avatar), is given an apartment which acts as the home base throughout the rest of your Onverse play.
This game includes many virtual socialization features. For example, you can meet up with other players and go shopping, visit stores, etc.. Upon completing tasks and doing other related assignments, you can earn reputation and game points. Aside from all of this, Onverse offers countless other options, and even has in-game games, in which you can compete or team with other players.
If you like social games, such as the Sims and Onverse, you may also want to check out vSide, another free game for iMac. Although this game is quite similar to Onverse in nature, it does have a completely different UI, controls, features, and more.