Hackers and hacktivism can be summarized as follows:
1) Hacking involves unauthorized access to computer networks and systems, while hacktivism uses hacking for political or social causes.
2) Notable hacktivist groups include Anonymous, which has targeted government and corporate websites to support political protests and social issues.
3) Different types of hackers include black hat hackers who carry out computer attacks, while white hat hackers use hacking for security testing with authorization.