Hacking is defined as: 'A person who illegally gains access to and sometimes tampers with information in a computer system. (Merriam-Webster's Collegiate Dictionary)

Many hackers take exception to being lumped together in one group. They are quick to point out that the underlying intent of the break-in needs to be considered. That say that the "real" hackers attack for the purpose of exposing weaknesses rather than doing real damage. Fueled by insatiable curiosity, their exploits are rationalized as actually helping make systems more secure. to their way of thinking, they are the good guys.

Hacking is a felony in Canada and the United States of America and most other countries. When it is done by request and under a contract between an ethical hacker and an organization, it is okay. The key difference is that an ethical hacker has authorization to probe the target.

Novice Hackers 
These folks make up the largest segment of the hacker population. Hackers of this group are sometimes referred to as script kiddies because they rely on scripts (preprogrammed routines) developed by more knowledgeable hackers to run their attacks. The stereotype for this segment is that they are most often adolescents who have little understanding of what they are doing or the impacts of their exploits.

Intermediate Hackers
These folks have a far better understanding of what they are doing. They may posses significant computing skills but lack the experience of the real experts. They are capable of great damage and since the may aspire to reach the "next level" they may be highly motivated to strike high profile targets.

Elite Hackers
These folks are capable of penetrating most systems. They understand the inner works of major commercial systems and are able to dream up new exploits, whereas novice and Intermediates are more like simply take advantage of well known tools, techniques and exploits. The elites are on the cutting edge of the "field" and are capable of devastating results, if sufficiently motivated. Thankfully they are not always so inclined.

Some estimate that there may be as many as 250,000 clueless hackers, 10,000 skilled intermediates and anywhere from 1000 to 2000 hacker geniuses. (2000) these numbers may be a lot higher . the bottom line is that a hacker at any level can potentially do damage , albeit for different reasons. You should fear elite hackers because of their skill and novices because of their lack of it

Portrait of a Hacker
Another way of classifying hackers is based on the underlying psychology that drives them. The most prevalent group, "cyber punks" are the group we have the most information to base opinions on. For them hacking is  merely a hobby. Obsession and criminal intent are missing from any accurate description of their activities. They break in just to see if they can, but would never intentionally harm the system environment they have targeted. They believe they have done no wrong despite evidence to the contrary. The fact that they committed the cyber equivalent of 'breaking and entering" is lost on them. They are often oblivious to the unintended consequences that they have caused. Like the dog owner that allows their pets to chase after strangers  and offer up only the hollow reassurance that "it's okay, they won't bite', this type of hacker is perfectly willing  to let the victim assume the risk of whether the incident will be injurious or not. The point being that this seemingly mischievous behavior can have grave consequences.

This group tends to be awkward in social settings where close contact is required. some may even be down right antisocial.( with notable exceptions, some excel at "social engineering to gain access to computer systems. This may be a future writing.) Behind a keyboard some hackers feel freer to express their feelings. Cyberspace represents an environment that is far less threatening. The consequences of rejection can be easily deflected or ignored altogether. They can say what they want to whomever they want, and the worst thing that can happen is that they may start a "flame war" ( a war of words) Arrogance is never in short supply. Unencumbered by physical or emotional limitations they can be what ever they want in a virtual world. They create alter egos and hide behind imaginary identities. If they want to believe they are the rulers of the universe, cyberspace gives them  a venue where they can escape to that more desirable position. Many believe that "cyberpunks" make up the vast majority of the hacking community. For this reason it is their image that is most often imagined when the term hacker is involved. Cyberpunks are most often males in their teens and early 20's. However they come in all shapes and sizes. Some have grown up ( at least in terms of their physiology) and have regular jobs, often in the IT industry. A smaller percent gravitate to more sinister activities and become cyber terrorists or professionals for hire.

These are they general tendencies that describe the hacker community as a whole. how ever due to their secretive and relative lack of organization, conclusive studies remain elusive. Thus  for any given hacker, "your mileage may vary".