The preconceptions suggested by this term often include ideas such as white men's inferior physical prowess in certain traditionally non-white sports, white men's awkward social behavior (especially around black and other non-white social groups), white men's tendency to pursue certain careers, hobbies, musical interests, political affiliations etc., which differ from those of their non-white counterparts, and countless other indicators which may or may not have a basis in objective reality.
While the term may occasionally be used by non-whites to express actual hostility at white people over historical racial issues, the trend has been toward a more playful, even ironic, use of the term. It is not uncommon to hear a black person use the term affectionately when speaking of a white friend, or even to hear two white people using the term in reference to each other and/or themselves.
As the slang term described above, this two-word expression generally appears in spoken dialog only. In official written English, a white boy requires the preceding article (a, the) and means only a young male who is white.
NON DEROGATORY: "Yo Slim! You know your my favorite white boy, right?"
Clarence: Fuck off nigger! Back of the bus!
J-Dawg: Yo imma cawl tha 5-0 on this muthafuckin craka's ass.