COVID 19 is no more stoppable but slowing it's diffusion is a priority and would make the difference.<p>Why not create a 'haveibeenpwned.com' like website service to help slow down COVID 19 diffusion.<p>Many of our mobile phone keep tracks of our daily movements. (give a check to your https://www.google.com/maps/timeline )<p>Medical authority can have write access to the service and upload anonimous location data of last days of people confirmed affected.<p>Any people can install an app that on daily basis compare location and timeframes with the ones confirmed and uploaded by authorities.<p>The app allert with a warning people that match location and timeframe of infected people giving details about the match.<p>People can than contact local authorities that can give more information or invite to voluntary quarantine.<p>This would not be a perfect. Many people don't have traking data. Many people would not use the service. But every infection that prevented would slow down diffusion and save lifes.