When you throw up this sign, your finger placement is supposed to form the letter "W" which stands for Web. Its similar to how the superhero Spiderman bends his fingers to shoot a web. Also, you have to hold the back of your hand out in front of you and keep your palm towards your body with the thumb curled in; this is what differs it from the popular Horns hand sign which is used in the Metal rock scene. Spread out your pinky and index finger while raising the two middle fingers slightly up in order to do the W the right way.
This used to be a gang sign for the thugs and hoodlums who made their money on the 178th block as well as the projects near 170th Street. But now, kids from not just Webster Avenue, but from all over the BX can be seen throwing this sign up as a greeting or to say goodbye, or even as a facebook picture or whatever. But it should be a known fact that this trend mos def started on Webster Ave!