I don’t know if your data model (or general hypothesis) is working. There are some truly garish color combinations (too many to be a fluke) on the site, so I’m thinking some colors work better as part of a work rather than as a stand-alone palette
Yes, some are pretty funky :). Gradients, photographs etc can be one reason. Still I think some are pretty nice :).
I don't know how you're doing the palette extraction right now, but if want something to experiment with I'd suggest you take a look at using k-means clustering. In other words see the set of pixels as points in a 3D space (where the axes are red, green and blue) and then perform k-means clustering on the points. You could then extract the palette from the centroids. If k-means doesn't give satisfactory results, try spectral clustering.
Sounds cool, thanks :)! I'll look into some more methods soon!
As a research result, this is still an interesting outcome. Nobody has done this before, to my knowledge.
German tricolour flags are prominent here (current and German Empire). I think that's an interesting result. There may be more national flags, I was looking for something similar to the Spanish flag, but my knowledge isn't that great there.