Hi Tim,
We're making changes now that restrict how big community curated places can be. The creation of large 'continent size' places like some of the ones seen here really do a number on our system. And now that we have a standard set of places and nicer bounding-box query capabilities the creation of any more really big places shouldn't be necessary. It would be great to get rid of some of these duplicate continents, but it turns out alot of people are using them (projects etc.). If you are using them and want to migrate any content to the new Standard continents that would be a step in that direction.
There's also alot of duplicated Administrative level data from previous imports from GADM that we made back in 2013 and couldn't match when doing this recent Standard update that we're slowly cleaning up. There's also a lot of really good park data in here that I hope we can find better ways to surface.
Scott