The film takes place in a small German town during the year before the start of the first World War. A series of incidents has the town rattled and skeletons start coming out of the closet.
The white ribbon of the title represents the innocence of childhood and it can be said that innocence, and the loss of it, is one of the major themes of the film.
I believe this is a film that requires multiple viewings to fully grasp what's going on, especially since there were still some unanswered questions as the film's final shot faded to black.
If anything, I can now say that I support this film to pick up the Best Foreign Film Oscar and I look forward to that eventual second viewing.