The italian has been around for a very long time, it aims to hit blacks weakest spot, (f7), and create different kinds of attacks. The Ruy Lopez seems to be the most common after 1.e4 e5 2.Nf3 Nc6, however if white plays the ruy lopez he needs to know alot of theory, because black has lots of gambit lines against the ruy lopez. So if white wants to build up a good position with attacking potential without allowing black such drastic counterplay then the c3 and d3 italian is a great option. in its nature its looks slow, and some call it a delayed ruy lopez, however black needs to tread carefully or he will find himself a victim of a very large kingside attack. This is exactly what happened a few weeks ago in my game against Justin Tan. He played typical moves that are 'supposed' to equalize for black, made a move order inaccuracy and found himself very quickly getting crushed with a MASSIVE yet so logical attack. Although i missed the queen sac that would lead to mate i still managed to win 3 pawns which was easily enough to win the endgame comfortably. The thing to understand about this system, is that you wont always get a large attack, but white will always get a good centre, along with kingside play. it is almost like playing a system because your aim is to have knights on f3 and g3, with the light squared bishop on the a2-g8 diagonal, and if black tries to trap or remove the bishop from there then it will always have a safe square on c2 where it supports the centre and a kingside attack when the centre opens as it innevatably does when white plays d4 at the right moment.
Currently in grandmaster practice there is really ony one way for black to solve all his opening problems, and it is by getting his knights to f6 and g6 copying white so he can try and play c6 and d5. Black can try to play actively by playing d5 quickly but he needs to be ready to both defend his e pawn as it will become weak and a new target of attack, but even if he does this succesfully white can always play d4 and resovle any activity problems he might have, in which case still often gets a better game. For tactically sharp players it it a good opening as they can play without worry of counterplay. The key to remember is that the f5 square is a key in any attack in this opening and white tries to occupy this square with one of his knights, as both can get there easily and black cant easily contest this square. Here is my game with Justin Tan who is rated 2160 fide, showing that even really good players can fall victim to this seemingly quite opening, while it was not perfect play it is very instructive. all the key ideas that i have mentioned above, and i mean ALL of them happened in this game and black got crushed. beacause of the nature of the opening there arent so many opening lines to talk about but the ideas can make it a tricky position for black to play. If black does manage to 'equalize' with the main plan and obtain a fairly symetrical position, then white needs to understand that and such position is in his favour as it will be his turn to move.