Anonymous... 
Source: http://www.ourcuriousworld.com/TypesofGhosts.htm#ps3
The first and probably most commonly understood type of 'ghost' is that of the deceased human being—usually of someone known to the observer such as a friend or family member 1 (though they may also be strangers or 'historical' figures as well).
This type of ghost appears not only self aware and intelligent, but capable of interacting within the linear world of time and space; interactions which may include making itself visible (manifesting), being heard audibly or telepathically, and even of being capable of touching the living (tactile capabilities). Some ghosts even seem capable of manufacturing odors (such as tobacco, perfume, or after shave) that were associated with them when they were alive.
Further, just as human beings are capable of displaying a whole range of emotions and temperaments, so too is a ghost. Some may be playful and loving while others are dark and angry. Often they are described as brooding, sad, or melancholy, and are seen even to exhibit such very human emotions as rage, fear and jealousy. As such, an encounter with a ghost may be either a pleasant experience or a frightening and disturbing one, depending upon the nature and temperament of the ghost and the circumstances of its manifestation (as well as the emotional state of the observer.)
In general, however, ghosts are usually considered harmless and, in some cases, even beneficial, and should be treated with the respect and dignity accorded to any human being, be they living or dead.
Therefore, since such ghosts apparently retain much if not all of their former earthbound personality, be it positive or negative, and are capable of feeling emotions such as love, joy, anger, guilt and regret, I (authour) think a better term for a non-corporeal or disembodied consciousness that is clearly human in origin should be a personality rather than either 'entity' or the more generalized term 'ghost'. Personality captures the essence of what this being is; it is a 'person' who simply no longer resides within the context (and some might say, the confines) of the physical body. As such, to identify such a presence as a personality is simply to acknowledge its inherent humanity.
Personalities are further divided into several sub categories, largely determined by their relationship to the viewer.
Those of a recognized family member or friend who have passed are called familial personalities because they are intimately familiar to the witness. This would be a parent, a spouse, a child or a close friend, or someone otherwise known to the witness, and are probably among the most common type of manifestation seen. Accounting for the vast majority of all sightings, familials are also not only the most common type of ghost, but are often the most short-lived variety as well; they are frequently seen but once, usually to a grieving spouse or parent, assumedly as a means of saying farewell or in an effort to comfort or reassure the bereaved.
Unfortunately, the fact that they are often not seen or experienced repeatedly makes them among the most difficult to confirm or study, since no return appearance is usually anticipated. Of course, sometime familials will make more than a single appearance, though this is less common; in most instances, they appear to have a specific agenda in mind, and seem to interact only to the degree that they are trying to comfort the still living.
1. Please refer Her last visit in this web site.
Source: http://www.ourcuriousworld.com/TypesofGhosts.htm#ps3