Wikipedia Brown
A person who fancies himself an expert in many things but whose expertise derives largely or solely from the internet. The shallowness of his/her knowledge base is often betrayed by obvious factual errors. (The antithesis of "Encyclopedia Brown", the fictional boy detective in the eponymous literary series.)
Jim: Did you know that scientists found vestigial wings in a mummified komodo dragon?
Hal: You're a real Wikipedia Brown.
Hal: You're a real Wikipedia Brown.