Hi!
A few months or weeks ago, i mapped a relatively new street of which I had quite precise geometry data. The aerial images of Bing Maps are still too old for mapping, you can only see grassland at this position. However, the street already existed in Bing Maps before i mapped it, but it was totally unprecise. Now, i visited Bing Maps again, to see whether they updated their aerial images. I was surprised: It seems as if they copied the almost exact course from OSM into their own maps.
They are not allowed to do so without naming OpenStreetMap as a data source and adopting an appropriate free license. As far as I know, they currently do neither, so they cannot be using OSM data legally.
However, if we were to claim that they copy our data, we would need much stronger proof. Can you link to the place where you have made that observation?
Sure I can: https://www.openstreetmap.de/karte.html?zoom=18&lat=53.78644&lon=9.99414
I didn’t find a way to create a permalink to Bing Maps, though. Also, it could be that my memory is wrong about what the Bing Maps were like before I updated OSM. Perhaps I mixed it up with Google. So of course, this is not a proof at all. It’s more an occasion to keep eyes open.