There Are Quite A Few Theories In The Paranormal Field About The Differen't Types Of Hauntings And What They Mean.  Listed Below Are The Two Most Common Forms Of Hauntings That Are Often Found At Haunted Locations.

Residual Haunting: This Is A Type Of Haunting That Repeats Itself Over And Over.  A Haunting Like This Is Like A Stuck Record Player That Plays The Same Song Over And Over.  A Haunting Of This Nature Usually Will Not Recognize You Or The Fact That You Are There.
Intelligent Haunting:  These Are The Types Of Hauntings That Interact With You And Actually Recognize You Are There.  The Spirits Will Often Play With You By Responding To What You Are Doing.  They Are Harder To Explain Away By Any Other Natural Causes. We Have Experienced Both During Investigations.

Poltergeist:  German For "Noise Ghost".  These Hauntings Often Involve Objects Being Moved, Or Thrown.  Thes Can Be The Most Volitle Type Of Hauntings And Sometimes  Lead To Bodily Injury.