Why is Bishop c4 a Good Move Early Game?

I've seen a lot of people playing bishop c4 lately as part of their openings. Why is this a good move and how is it countered? Thanks.

because it's part of Italian opening and also an active square for bishop also clears the way for short castle moving the bishop

counter would be using queen side knight to get rid of it this bishop is dangerous as it generates tactics with help of other pieces its annoying for the defender

Rather than a good move, Bf1-c4 should be considered as a component of some opening systems. There are situations where it is not that good, and some others where it's plainly wrong.

In general, Bf1-c4 is good when White can develop active play or restrict Black's play along the diagonal a2-g8. But if there's no "follow-up" for White on a2-g8 or Black can advantageously harras the bishop with pawns or pieces, thus winning free tempos, it may not be that good to expose the bishop on c4.

I'm guessing you have never seen nor read a chess book. You should check them out. 

As an example of Nicator's point (that Bc4 is not uniformly good), consider this line:

It puts pressure on f7. f7/f2 are considered weak squares in the opening because they are defended only by the king. There are a number of attacking and sacrifice ideas that exploit this in the italian game. Fried liver attack is a well known one. Look up some lines in the italian game. Plenty of sites explain it. if you want develop your kingside quickly and castle c4 and b5 (Spanish game / ruy lopez) are common places for the bishop.

Some ways to counter it are delay nf6 so blacks queen can keep control of g5. A comon attack is for white to add more pressure to f7 by playing nf6. You can also defend f7 with nf6 but this puts your knight on the rim and looks awkward. A good line is to meet bc4 with bc5, then nf6, then castle. Once castles f7 is defended twice ( king and rook) and nf6 blocks the queen if she comes to d3 which you sometimes see.

sorry. typo. white adds pressure with ng5 not nf6.

and nh6 defends f7 but puts your knight on the rim. what is wrong with my phone.

queen comes to f3. look dont listen to me. my predictive text is sabotaging everything. watch you tube instead.

no chess notation so I'm safe. look up the traxler counter attack for ideas on how to turn your opponents ideas back on them. traxler requires accurate play and an attacking mentality. it's not for the faint hearted.

I assume we are talking about Bc4 after 1.e4 e5. Particularly after 1.e4 e5 2.Nf3 Nc3 3.Bc4. In this case, Bc4 is a logical move that follows basic opening principles. In the opening you want to fight for the center, develop your pieces to active squares, and get your king to safety--usually by castling king side. 3.Bc4 develops the bishop to an active square. aiming at blacks most vulnerable square  and prepares for king side castling. 

Thanks for all the comments. I watched some videos on openings and development and now it makes more sense.

Bc4 for white attacks blacks f7 pawn, the weakest pawn for black