GmapGIS is a free tool for marking and drawing on maps without having to create or use a Google account. GmapGIS provides tools for drawing lines and shapes, adding markers, adding labels, and measuring distances. To get started just visit GmapGIS and select the drawing or labeling tools that you want to use. When you are finished drawing on and labeling you can share your map by sending the link that is automatically generated for your map. You can also save a KML file for your map and view it in Google Earth.
Applications for Education
GmapGIS could be used by students to identify and label places without having to create an account. They can share their work with you by using the links generated for their maps. Students could also use GmapGIS to quickly measure distances between places on a map.
H/T to Google Maps Mania.