Sometimes spammers post platitudes as diary comments trying to link back.

It’s pretty much the case 95% of the time, which is why it should no be that complicated to detect the spam even if it is in a different language. I mean there is really no good reason why a diary should link to some polish furniture store and if in doubt you can still check the profile it usually always has zero map edits.

Could you somehow add a system that requires an account to have a certain age and/or a few edits? Or maybe a report button?

SPAM

Stuff like this has no place in OpenStreetMap. Applications using the map should add that information if seems useful for their purpose.

SPAM

Mh…k.