Scotch Gambit

The Scotch Gambit and the King's Gambit Accepted are similar in that they both are focused on attacking f7 which is Black's weakest square. In the KG White weakens himself by moving the f pawn making for a strongly tactical game where Black has good chances of seizing the initiative and winning. In the SG White does not move the f pawn at all and thus has a more stable position and can thus attack Black with less chance of counter attack. Once Black takes that Pawn he finds himself in trouble because the Scotch Gambit is used to achieve favorable positions in the Giuoco Piano and the Two Knights Defense via "Desirable Routes."   The best thing for Black is to avoid the SG by transposing to the Two Knights' Defense  or the Guioco Piano.  If Black does not transpose he will find himself in a difficult game wherein he becomes the brunt of a King Side attack. 

 After: 1. e4 e5 2. Nf3 Nc6 3. d4 exd4 4. Bc4

This is the main line idea that White is aiming for!

1. e4 e5 2. Nf3 Nc6 3. d4 exd4 4. Bc4 h6 5. c3 dxc3 6. O-O cxb2 7. Bxb2 Be7
8. Qd5 d6 9. Qxf7+ Kd7 10. Be6#
{White mates} 1-0

After 4. ...Bb4+

4. ...Bc5 transposes to the Giuoco Piano