hacking is exploring and cracking is bypassing software copy protections and everything else is just criminal
"Cracking" is also a term used to describe malicious hacking in general. It's used by people like ESR who are absolutely outraged the word "hacker" is ever used to describe anything negative. The rest of us, who realize that after 20 years the word "cracker" just isn't going to catch on, don't care and use the word "hacker" interchangeably. Language is defined by how it's used, not by a tiny irate percentage.