|What is a hacker?
Hacker: Computer and network security
A person who exploits systems or gain unauthorized access through clever tactics and detailed knowledge. See: Hacker (computer security) and Black hat.
Other hackers often viewed negatively, include phreakers and software crackers.
White hat: those who attempt to break into systems or networks in order to help the owners of the system by making them aware of security flaws, or to perform some other altruistic activity.
Hacker: Highly skilled programmer
The positive usage of hacker (the historically "proper" usage) is one who knows a (sometimes specified) set of programming interfaces well enough to write software rapidly and expertly. This type of hacker is well-respected, although the term still carries some of the meaning of hack, developing programs without adequate planning. This zugzwang gives freedom and the ability to be creative against methodical careful progress.
At their best, hackers can be very productive. The technical downside of hacker productivity is often in maintainability, documentation, and completion. Very talented hackers may become bored with a project once they have figured out all of the hard parts, and be unwilling to finish off the "details". This attitude can cause friction in environments where other programmers are expected to pick up the half finished work, decipher the structures and ideas, and bullet-proof the code. In other cases, where a hacker is willing to maintain their own code, a company may be unable to find anyone else who is capable or willing to dig through code to maintain the program if the original programmer moves on to a new job.
Additionally, there is often a social downside associated. The stereotype of a hacker as having gained technical ability at a cost in social ability may have an uncomfortable amount of factual foundation in many individuals. While not universal, nor even restricted to hackers, the obsessive/compulsive nature, difficulty in relating to other individuals, and often abrasive personalities of hackers make many of them difficult to work with or to organize into teams. Some within the hacker community have speculated that some mild form of autism may be involved. In one more pronounced example of such, Bram Cohen, developer of BitTorrent, has been diagnosed as having Asperger's syndrome. However, no formal studies of autistic tendencies in hackers have been done.