The first place you should probably send somebody for reference would be the most official body of reference for the subject. For example, if somebody was asking about a particular HTML tag or something about the HTML spec, their first stop should be that spec (as an example, and there are lots of page anchors throughout that spec to navigate directly to what the user needs).
Examples can often be quickly found via Google. If the Google results are clearly plentiful and seem pretty good, then just linking the user to the Google search itself would work fine. (And may subtly nudge them to use Google a little more thoroughly, though keep in mind that SO generally doesn't want its answers to just be "just Google it" so use tact and offer additional information beyond just the search.)
