They can talk to other objects. Therefore they are more like people and cats than like rocks and trees. You will probably find it advantageous to think of objects as if they were real rather than electronic. Thinking of them like people is a pretty good metaphor. Metaphor is important since it helps you with a framework for thinking about something unfamiliar.
Every metaphor breaks down at some point, however.
Just like people objects are active. Just like people we can make requests of them. Just like people they themselves control what they do. Just like people they remember stuff and they do stuff. Most objects, though they can be active, are pretty passive.