url URL date NUMBER NUMBER NUMBERtNUMBER NUMBER NUMBER NUMBER NUMBER security in cyberspace is a different kettle of fish compared to many computer systems cyberspace entertainment only has to be useful to the majority of its users entertaining that means it can tolerate a small amount of vandalism still remain useful this is quite unlike a system required for commerce we still have a headache of course but at least we only need to keep the system around NUMBER percent clean rather than NUMBER NUMBER percent of course we ll still strive to stamp out corruption but our system failure threshold is more achievable than one might at first assume 