Map Rating-similar to Player rating.
This will work same like for people rating,this mean that when you finish some game in map,then you can add this map on yours favourite map list,except that player will have 5 free slots(or 10),where he can add or remove maps from list(like in frend and foe list).
And when you go on Game finder,then there when you press some map, can show how many these map have favourite points.
If i dont write something good,then you can help to improve this description.