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