Young children love to be around other children. Put your toddler in a room full of kids she feels comfortable with -- older or younger -- and you'll see the delight on her face and the way she mimics or laughs at things the other children do. What you probably won't see much of is sharing, working together on an activity, communicating with each other, or what we would consider playing "with" other kids.
This is called parallel play, and it is completely normal for this stage of development .
Children are often close to 3 years old before they begin taking turns, sharing toys, and engaging in what's called collaborative play. Until that time, your play dates may involve two children who don't seem to care too much about each other, but in their own way, they are learning from each other and developing important social skills.
See Also: Parallel Play | Collaborative Play | Functional Play | Constructive Play | Dramatic Play
Also Known As: side-by-side play
My child loves to play trains with his brothers but he does it in parallel play mode, moving his trains near the other kids' toys but not really interacting with them.