yeah, when i looked it up before posting i was a tad surprised to find that 'obsolete' is a word; i've always heard it as 'obsolesced'.

a related question that's always bothered me (could be a YART, i didn't LIU): whence "86'd"? i first came across the term when i was waitressing; the manager would scribble on a board that a particular dish had been 86'd when they ran out of it. i suppose that would've been right around 1987, so it made perfect sense... but i still hear it. why'd that year stick??