When you start a song with a solo instrument, the choice of where to place it in the stereo image is not easy. Leave it in the middle and it will get in the way of the vocal-snare-kick-bass when they come in, so then you have to EQ it so that it occupies what [little] space they leave, or have it move off to one side. Or, you can start it panned left or right to a greater or lesser extent, but then, in those first attention-seeking moments of the intro, it can just sound like one speaker has stopped working. You can add width by using various plugins like stereo chorus, but how about adding width by adding depth? This video looks at panning the reverb send of a mono guitar track to push the balance of the processed guitar to the opposite side of the stereo image to provide a wide, but natural sounding, intro to the song in question.