Anyway, this led me to find an online test (made by actual real prosopagnosia researchers so it's not like a Myspace WHAT COLOR IS YOUR INNER FURRY thing or whatever), which I scored 67% on (65% is their threshold for "you are almost certainly faceblind"), and there's probably enough of a margin of error that I am comfortable saying that this shows I'm probably faceblind. Hooray.
It's not that I have profound prosopagnosia. I am able to recognize people who I spend a lot of time with. My friends and coworkers, for example. Of course there it helps that I have context with which to learn who's who very quickly. My first day at my job, I had to "fake it" with ucblockhead for a while — even though I'd met him before getting this job and had known him online for years. Although, there was the time the guy who sits next to me got a haircut and trimmed his beard... it took me a few moments to realize that I knew him and he wasn't just some crazy guy who managed to get into the office somehow.
This is probably a big part of why I draw my comics the way I do. My journal comics portray people with various features which I find easy to keep straight in my head (although I don't actually come up with those features until I need to draw someone). My fiction comics generally have characters which look as completely different as possible, using hair/skin colors, horns, tails, and so on to keep them straight. The color aspects in particular are important enough to me that I have a color palette file which I use to keep the colors consistent.
I'm sure that all of my various mental weirdnesses are related. The sort-of-but-not-really-hyperlexia is almost certainly related, and I wonder if the asexuality and general dysphoria/dysmorphia are too. (Of course, that has often manifested itself as me not really recognizing myself in the mirror or photographs, so, yeah, probably. Also, this person's experience seems frighteningly familiar.)
I don't think there's really any "treatment" or any reasonable thing to do except to practice as much as I can, and try to figure out ways of making people know that if I don't recognize them it's not because I'm not interested in them — I just need a reminder of who they are (via an event or a common friend or whatever), because that's how my brain is wired.
James "Kibo" Parry's rant about it also seems completely familiar to me, in terms of how I learn peoples' faces and how it differs from how most people seem to.