One way to look at this list is that if you did a 30 team fantasy draft, the top 90 players would be the top 3 players selected for each team.
It would make more sense to make the list the top 90, but of course that's not as cool a number as 100.
Spots 91-100 are basically the first part of the fourth round of a hypothetical fantasy draft. Assuming, of course, that every team was drafting based on trying to win games this season.
Rob Covington in the top 50 means that he'd be taken in the 2nd round as the #2 player on a team trying to win right now. That, uh, doesn't quite sound right to me.