domain vs www.domain?

[Jesse Hires]

I'm seeing a lot of duplicates where a single site is getting recognized as
two different sites. Specifically I am seeing www.domain.com and
domain.combeing recognized as two different sites.
I imagine there is a setting to prevent this. If so, what is the setting, if
not, what would you recomend doing to prevent this?


Jesse

int GetRandomNumber()
{
   return 4; // Chosen by fair roll of dice
                // Guaranteed to be random
} // xkcd.com