?! These used to be called little ears. Bc4 or Bb5 is more to the point. Black's knight doesn't threaten much on g4, getting the bishop out allows castling and helps control central squares.
4... Bf8b4 5. a3
?! This isn't great, black is being forced to do what he wants to do anyway which is remove protection from the e4 pawn. e3 or Bc4 or Bb5 all look playable.
5... Bb4xc3 6. dxc3
It's probably better to take with the b-pawn here as this leaves more pawns in the centre.
6... d6 7. Bf1c4
Bc4 is perfectly reasonable here, but Bd3 deserves serious consideration. Using a bishop as a big pawn is never good, but losing the e4 pawn is worse here.
7... O-O 8. O-O Nf6xe4
Black takes the pawn.
9. Nf3g5
?? This just drops a piece, Re1 with ideas of Be5 looks best.
9... Ne4xg5 10. Qd1h5 Ng5e6 11. Rf1e1
f4 might be worth trying.
11... d5 12. Bc4d3
?! This fails to anticipate black's obvious reply which is...
12... e4 13. Bd3e2
I'm not convinced this is the right square for the bishop. Bb5 looks better to me.
