Talking with admissions officers

alot of you have recommended staying in touch with admissions officers during the application process. but what exactly are you talking about? does that mean that i should be calling the admissions office and asking if they are seriously considering me? at what point does this get annoying to the admissions people? i'm a little confused, and a little wary about doing something like that. it seems to me that i could do as much harm as good by pestering. any thoughts?