Hackers, crackers and coloured hats
'Hacker' is possibly one of the most controversial terms in computing. There are but a few others that have been so much disputed and that have so many different definitions and understandings. Initially the word probably meant a carpenter (one that hacks wood), but it is been also used to mean radio amateurs, telephone tweakers, collectors and spreaders of illegal software, top programmers, networking gurus. It has also denoted professionals in any given field or just original pranksters...
The mainstream media depicts the hacker as an intelligent but malicious person who has mastered the dark arts of breaking into computers. For cyberpunks, the hacker is a network anarchist. For warez d00dz dealing with illegal software a top hacker is able to gather the newest titles and deliver '0-day warez' (explained below).
But probably the most authoritative definition is given by the people who largely built most of today's Internet and its infrastructure. The Jargon File defines hacker as
[originally, someone who makes furniture with an axe]
1. A person who enjoys exploring the details of programmable systems and how to stretch their capabilities, as opposed to most users, who prefer to learn only the minimum necessary. RFC1392, the Internet Users' Glossary, usefully amplifies this as: A person who delights in having an intimate understanding of the internal workings of a system, computers and computer networks in particular.
2. One who programs enthusiastically (even obsessively) or who enjoys programming rather than just theorizing about programming.
3. A person capable of appreciating hack value.
4. A person who is good at programming quickly.
5. An expert at a particular program, or one who frequently does work using it or on it; as in ‘a Unix hacker’. (Definitions 1 through 5 are correlated, and people who fit them congregate.)
6. An expert or enthusiast of any kind. One might be an astronomy hacker, for example.
7. One who enjoys the intellectual challenge of creatively overcoming or circumventing limitations.
8. [deprecated] A malicious meddler who tries to discover sensitive information by poking around. Hence password hacker, network hacker. The correct term for this sense is cracker.
So for this company, a hacker is a professional with original thinking, lots of competence and attitude. Although most hackers work in IT, the definition does not limit it to computing only - hackers may find 'soulmates' among likely-minded musicians and physicians, artists and mechanics.
So although different opinions exist, this writing uses the definition above - as hackers in this sense have most influenced the development of computing, be it then new standards (Ethernet and Bob Metcalfe, Web and sir Timothy Berners-Lee) programming languages (Perl and Larry Wall, PHP and Rasmus Lerdorf), operating systems (GNU and Richard Stallman, Linux and Linus Torvalds, OpenBSD and Theo de Raadt) or revolutionary ideas (Richard Stallman, Eric Raymond, Lawrence Lessig and many others). What comes to the infamy coming from breaking in and stealing things - building is remarkably harder then pulling down, so the 'bad guys' are called 'crackers' by the real hackers and frowned upon (an occasionally-used spicier term is 'lower life forms').