Yes OpenLayers is the leading OS project for web maps, in my opinion. PostGIS/PostgreSQL DB backend is also used often to offer writing/modification, besides WF

Yes OpenLayers is the leading OS project for web maps, in my opinion. PostGIS/PostgreSQL DB backend is also used often to offer writing/modification, besides WFS-T. But to draw/digitize the spatial data, it could be more practical to use a desktop software, instead of a web app.