Streetviolence.org lets victims or witnesses of a street crime to map the incident and give more details than are available on the police crime maps, like whether the victim knew their attacker and the time. The idea is to provide context to crime – if most of the muggings in an area are happening at, say 3am by people the victims know, there's little point in pensioners getting frightened about nipping to the shop at lunchtime.
Sadly, that's as far as we think its use goes. The charity behind the site, Witness Confident, says that it can be used by anyone who doesn't want to formally report a crime to the police. Putting aside that sound of a can of worms opening, part of the terms and conditions of adding a crime to the map is that you allow the police to contact you. There's the option to contact Crimestoppers if you want to report something anonymously, but the police crime maps also have that option. No wonder the Met, who worked alongside Witness Confident during streetviolence.org's creation, are withholding their endorsement for the time being.