Since cyberspace has become a type of public space, people have discovered it as a place for demonstrations. Cyberactivism ranges from inserting vicious pop-ups in undesirable websites to denial of service attacks and (sometimes very efficient) spoofs. Here are some examples:

Online occupation of Army careers office

Online Demo on June 20, 2001 against the airline Lufthansa because of their involvement in the deportation business. 13000 people participated. The Online demo was part of the ongoing campaign "deportation-class". Lufthansa is getting increasingly angry and has taken people to court - but their overreaction doesn't make them look very clever.

Denial of Service:
The electrohippie collective explains some aspects of present electronic anti war protests on its Iraq War Action Page. An example can be found here.

Cyberspoofs:
In early 2000, RTMark transferred Gatt.org--which people sometimes mistake for the World Trade Organization's official website--to a group of impostors known as The Yes Men. Since then, the Yes Men have been invited to several international conferences as representatives of the WTO. Here are pictures of one presentation.