The campaign's organizers, who were backed at the launch on Monday by Consumer Affairs Minister Ilse Aigner, say right-wing extremists have used social networking sites to air racist and anti-Semitic views, call for violence, reach audiences otherwise unacquainted with neo-Nazi ideas and to test acceptance thresholds.
Their campaign calls for user involvement in clamping down on such activities. Banners and buttons on participating sites encourage users to report racist posts, videos and profiles so that they can then be deleted, sending neo-Nazis a clear signal.
The list of 20 participating networks includes MySpace and the video sharing platform YouTube.
Users are also called upon to support victims in discussion groups and to contradict any racist and anti-Semitic viewpoints. They can also join groups related to the campaign.
The campaign comes after the revelation this summer that neo-Nazi activity on the internet in Germany has reached an all-time high. There were 1,872 known neo-Nazi websites in Germany last year, according to German media reports.
Aigner encouraged social networks to exercise their "domestic authority" to ban Nazis.
Far-right extremism has plagued parts of Germany, where there are about 26,000 right-wing extremists, according to the online portal "www.netz-gegen-nazis."
A group of suspected neo-Nazis tried to remove the sign for a street named "Jews' Alley" in the northwestern German city of Aachen this weekend, according to local police, while neo-Nazis in the town of Kleinmachnow near Berlin sprayed swastikas and other Nazi symbols onto a Soviet memorial.