Google docs urls that end in /edit will try and figure out what rights you have to the document and give you tools corresponding to those rights (to edit the do

Google docs urls that end in /edit will try and figure out what rights you have to the document and give you tools corresponding to those rights (to edit the doc, to share it, to add comments, to add suggestions, etc). Google docs that end in /preview just show the read-only view. When a doc becomes super popular, sometimes /edit will redirect to /preview.