Bishop's opening - what's the point of 4. Qe2? In Panov and Estrin's Kurs debuytov the following line is proposed in response to 3. d3:

[FEN ""]
1. e4 e5 2. Bc4 Nf6 3. d3 c6 4. Qe2


What's the point of 4. Qe2? Basically you should avoid moving the queen in the opening, which is the contrary here.
Black's main threat after 3... c6 is d5; it looks like Qe2 is an attempt to prevent that, by indirectly attacking pawn e5, even with check. However, I'm not so sure that it works as intended, because Black can play d5 anyway, e.g.

[FEN ""]
1. e4 e5 2. Bc4 Nf6 3. d3 c6 4. Qe2 d5! 5. exd5 cxd5 6. Bb5+ Nc6 7. Qxe5+ Be7 8. Nf3 O-O 9. Bxc6 bxc6 10. O-O Bd6


and Black's center control, slight development advantage and bishop pair provide more than enough compensation for the pawn.

I'd prefer a normal developing move (4. Nc3 or Nf3) instead of 4. Qe2.