Leaderboards: how do they work?
This is how the leaderboard currently works, as I understand it. Any one of which could be wrong.
1) Everyone has their own leaderboards.
2) Everyone on your board also has you on their board, as said by @rovionefuah. But most, if not all, the other people on the two boards have no one else in common. Therefore, your position on their board doesn't necessarily match with yours.
3) Everyone has their own set of objectives everyday.
4) The leaderboards are populated with people from any league level regardless of what league level you're in.