The iD editor is the de facto, browser-based OpenStreetMap editor. iD is fast and easy to use, and allows mapping from various data sources such as satellite and aerial imageries, GPS, Field Papers or Mapillary.
The iD editor is a great way to edit for small and easy changes that don’t require the advanced features of JOSM (a more advanced mapping editor).
Interested in participating? Email osmgeoweek@openstreetmap.us to learn more. Visit this site's Github repository