Stereo recording is a multi-faceted approach to recording that posits very realistic recordings in reward for distinctly challenging situations. It's not something we do or think about consciously, but basically any recording uses stereo in some sense.
First, let's examine this thing called stereo recording by dividing the term in half. We know what recording is all about, so we'll focus now on the stereo part.
Stereo means sound that comes from two sources or speakers to surround the listener and make him think it's coming from more than one place. It's basically the first version of surround sound, but with only two speakers. That's why they call the playback systems stereos.
Think of it this way - you have two ears, and they give you an incredible amount of detail. Try closing just one ear for a minute, and pay attention to all the sounds you hear. Pretty boring, isn't it? The second channel of information gives you detail in time and loudness that make the whole aural experience much richer than if you had two noses and one ear.
These small cues in time and loudness difference help us to pinpoint the location of sounds on a 3D level. We can point to a source in a 360 degree plane around us horizontally and vertically, and we perceive depth. All with two ears. This is why the recording world uses two channels (or more) in basically all recording releases.
With two speakers placed a small distance apart and a stereo track (remember, two channels here, left and right) you have a soundstage. Stereo recording exploits the sound stage by filling it up with voices/instruments at different places.
The most basic form of this is recording the tracks and mixing them to different positions in a stereo mixdown. This creates an articifial stereo experience, because everything was tracked separately and mixed together - it's not real. Stereo recording tries to emulate and reproduce a real sound, a real soundstage. Whether it's a choir/orchestra combination or a single classical guitar, we go for real. A real sound like that is pleasing to listen to, and it accurately reproduces the original performance.
Apart from the realness factor, logistical factors necessitate using stereo. For example, take a choir scenario: you have a 36 voice choir to record. There's no way you can get 36 mics in to record each person individually, unless your studio has bottomless funding. You have to do some sort of grouping and mixdown. You can learn more on the choir recording page.
So we use stereo in recording to reproduce a real, life-like, you-are-there aural experience that sounds pleasing to the ear. We do it because we have to sometimes, but because we like the sound.
Lee started his career in recording with an auspicious goal - record tracks of his own voice singing in harmony. As a hobby project, it didn't have the funding to go to a studio and pay for someone to do it for him. Like many of you, he pulled himself up by the bootstraps to learn the art of recording.