That's because the submission title is misleading (the blog post says nothing about "reverse engineering" anything.) Here is what flickr actually did: "Over t

That's because the submission title is misleading (the blog post says nothing about "reverse engineering" anything.) Here is what flickr actually did: "Over time this got us wondering: If we plotted all the geotagged photos associated with a particular WOE ID, would we have enough data to generate a mostly accurate contour of that place? Not a perfect representation, perhaps, but something more fine-grained than a bounding box. It turns out we can." So yes, they're just tracing around the points in their database to see what kind of shapes they will get, for the experiment of seeing how well they could represent a given (country, state, town) by connecting coordinates of photos taken closest to the real borders of those actual regions.