Every player that wins a game on the Map of the Week gets awarded that week's MOTW badge. As well, each win on the Map of the Week is worth points in a tally to determine the overall winner of the week. Here's the breakdown:
6 human MOTW win = 50 tally points, plus the gold badge
5 human MOTW win = 30 tally points, plus the silver badge
4 human MOTW win = 20 tally points, plus the silver badge
3 human MOTW win = 10 tally points, plus the badge
2 human MOTW win = 5 tally points, plus the badge
The MOTW page has a listing of wins for each player, with 6 human wins first, then 5, then 4, etc.
The player who has gained the most tally points at the end of the week is the winner of the Map of the Week.