As an adjective, random is defined in the Oxford English Dictionary as follows: "Having no definite aim or purpose; not sent or guided in a particular direction; made, done, occurring, etc., without method or conscious choice; haphazard." In other words, random is without pattern or objective; it's perfectly unbiased. To judge by the pop-culture usages cited above, however, the word has shifted away from its traditional usage, and now means:Paul's definition, to my mind, has some clear overlap with the OED definition (something done with no definite purpose, method or conscious choice is likely to appear unexpected or arbitrary to humans). But in any case, I resist the idea that the "pop-culture" usage of "random" is replacing the original meaning of random; rather, it's extending it. I can say "I had a random impulse to clap my hands" (meaning the impulse was unexpected even to me) or "There were a bunch of random guys at the lecture" (meaning I didn't expect them to be there), and I still know perfectly well what "random" means in the context of "random number generator" or "The prizes will be distributed randomly." The process is similar to other slang extensions of words that retain their original meaning ("cool," "hot," "killer," etc.).
b) Rare, strange, curated
c) Exciting, absurd, capricious
d) Unexpected, arbitrary, silly
e) Outcast, distasteful, unknown
f) Unlikely, unfeasible, impossible
g) Incongruous fun
A good indication that this new usage of random didn't arise as a misuse is that, as Hiebert points out himself, it's believed to have arisen in "computer-science geek" culture in the '60s: "[Ben Zimmer] located one of the first colloquial uses of random in the Massachusetts Institute of Technology's student newspaper, The Tech, from 1971. Here, the word random as an adjective meant 'Peculiar, strange; nonsensical, unpredictable, or inexplicable; unexpected,' and as a noun meant 'A person who happens to be in a particular place at a particular time, a person who is there by chance; a person who is not a member of a particular group; an outsider.'" If anyone knows what "random" "really" means, it's comp geeks.
A misuse, on the other hand, is a usage that arises when people guess at the meaning of a word or phrase they don't know, and guess wrong. Often, it's a logical enough guess that the misuse spreads and can overtake the "real" meaning in popularity. This is what happened with the phrase "begs the question," now more often used to mean "raises the question." It also seems to be happening with the word "feminism." I've come to believe that the average (wo)man on the street doesn't know what feminism really means. Due to the concept's bad PR, and the fact that it contains a feminine root, people guess that it refers to the belief that women are better than men. This is a new use, and a common one, but it's still a misuse, just like "begging the question."
It's probably not worth fighting over "begging the question," but I do think it's worth fighting over "feminism," because the misuse isn't just honest ignorance, it's a manipulation with political ends. It tells people that feminism is a crazy fringe movement whose members can be summarily dismissed, when in fact it's just a branch of civil rights.