What is a Hacker?
The hacker is a computer or electronics savvy person who uses their skill to test or alter the performance and function of a system.
Hackers may be those who build HAM radios from components, those who build custom systems from the board up, or people who improve their system performance by altering the software packages on them. Hackers may also test the security on an online system as a part of improving that system.
There is a large amount of controversy in the online community over whether crackers are a kind of hacker or not. Crackers definitely alter the performance and function of systems, but do so in a negative fashion.
To those who call themselves hackers, and have labeled destructive computer users as crackers the difference is simple. Hackers build systems, crackers break them, and a hacker is in no way a cracker.