I've always been aware that USB cords can both transmit data and send power back to the device, but I didn't know that microphone ports have batteries and that audio cords could work in a similar way. Wild.
So, again, what is the second ring on a stereo plug for? Maybe I should just look it up on Wikipedia... or maybe one of the rings is still for power, just in case. I mean, I guess there's no reason why I couldn't use one of my "line cables" to hook up a mic. So, maybe... it's the tip for one signal, the first ring for power, and the second ring for the second signal. But, then again, you said that, on some stereo mics, the second ring is for power, and so standard ports would probably have to support that, too. So, maybe... it can take a signal and send power on both rings? Man...
Yeah, I'm gonna look it up, haha.
EDIT: Learning a lot about the subject on Wikipedia. I don't mean to sound like a total novice, and please don't waste any more of your time answering my silly questions when I'm sure that there are plenty of excellent resources for this sort of thing online. Thank you for all of your help.
EDIT: By the way, if I sound like I have no idea what I'm talking about in some of my sentences in previous posts, it's because I've actually been referring to the black, insulated rings as the "rings." I honestly thought that this is where the conduction happened, despite the fact that the rest of the plug is the shiny, metallic... yeah. So, I've never used a "computer microphone," but I guess that I would have been confused by it because its tip would have looked like what I typically understand to be a "stereo" plug. This is because, unlike my stage mic, the plug has two black, insulated rings, which split the plug into three conductors: the tip for the output signal, the middle ring for power, and the rest of the plug (sleeve) for ground. As such, computer mic ports would have to be prepared for three-conductor plugs, just like line-in ports, although they'd handle these plugs differently. Apparently, MY mic ports must be able to use the ring for power and/or as another input signal, meaning that they can record in stereo, so, aside from sending power (can line-in ports typically do this?) and having a dedicated mic amplifier, they're no different from line-in: after all, if I plugged my mic into a line-in and amplified it to a huge extent, I could record from it.
I'm still a bit weirded out by the prospect that my mic ports MUST be able to send phantom power in order to be compatible with typical computer microphones, but they can also use that middle ring to record from, apparently.