OpenStreetMap is known for its openness, scale and diverse community. There are almost half a million editors, most using one of three desktop editing applications: iD, JOSM or Potlatch 2. This year, a challenger appeared. MAPS.ME is an open-source multiplatform application for using OpenStreetMap offline on phones and tablets. It's extremely popular, second only to pre-installed mapping apps. With this application we are bringing the power of open maps to millions of users, and now starting to direct that flow the other way: giving millions of casual users a tool for updating the map. In this talk Ilya will share a history of adding editing features to the app, some statistics and how this change has affected OpenStreetMap, both the map and the community. How bad is it when a horde of newbies comes ruining your map?