A point spread is the predicted scoring difference between a game's two opponents. If you choose the team that's favored, they must win by more than the spread number in order for you to get credit for a correct pick. If you choose the underdog team, they have to lose by less than the spread number in order for you to get credit for the correct pick.
So, if you pick Pittsburgh and they're favored to beat Dallas by five points, Pittsburgh must win the game by six or more points in order for you to get credit for the win. Otherwise, if Dallas loses by less than five, you wouldn't get credit for the win. If Pittsburgh wins by exactly five points, the game is a push, and no users get credit for a victory.
Yahoo! Sports uses the point spreads provided by the Associated Press. These spreads will be updated each day. Unless there are Thursday games, Thursday's lines will serve as the game's official spread. In weeks with Thursday games, Wednesday's line will be the official spread.
Please note that only Private Groups can elect to incorporate point spreads.