MyPlaces is free service for creating own collections of points on maps.
Collection points / places are basically you custom maps.
Maps used are from OpenStreetMap project
Offers various export and import possibilities - formats CSV, GPX, GeoJSON
Data can be this exchanged with navigation devices and GPS
Also provides some nice visualizations on the map - like clustering of points or Voronoi diagrams
Service is free and open source anyone can join or contribute