I was nosing around the map in Poland and noticed some oddities, what appears to be an import from some other DB alongside some manual mapping, giving rise to lots of redundant ways. Mostly the user-contributed stuff looks to have more detail for curved roads, but most of it has perfectly evenly-spaced nodes, suggesting a GPX-to-way conversion, and consequently there are hundreds of redundant nodes for arrow-straight roads. There a lot of name= where ref= should have been used too. The bulk-imported stuff neglects a highway= tag for roundabouts, meaning they're not rendered. I've done a wee bit of fixing up but as I discover more and more of I get the feeling I shoudl leave it for the local users to deal with the results of the bulk import and fix up their own stuff.