I discovered it in the Flickr Blog and followed it up with considerable Googling, but I can’t find any love padlocks in SF, much less a popular location for them. The Wikipedia article lists two dozen notable locations in Europe and Asia, but not one in the Americas.
I searched Flickr’s San Francisco map and found two almost promising photos: an unrelated collection in the mission that was removed by municipal workers in 2005, and this one in my backyard that I plan to confirm shortly.
But, considering the colorful cities in Wikipedia’s list, is no one else surprised that SF isn’t among them?