The Oxford English Dictionary is appealing for help from the public in tracing the earliest appearances of words. What they're looking for is documentary evidence of when a word was first used, so at the moment they're after evidence that disco appeared before September 1964, FAQ earlier than 1989 and a few others.
You can read more on the OED blog or follow them at @OEDonline to find out how it is progressing. Apparently, they've already found an earlier appearance of FAQ just today.