Daniel P. B. Smith wrote:
- I regard someone as an expert if they can show me that they can
accurately convey detailed information on a topic directly from memory, and when needed can remember or quickly rediscover the source from which they that got that information. Think of a lawyer who cites a legal decision, or a minister who can literally "cite chapter and verse."
- Someone who has done so much valuable work on a topic that he is
cited as a source by many others, either formally (in a print citation) or informally (someone telling you "go see so-and-so about that.")
This is a really great answer.
Completely pointless post, but there you go.
-Jeff