Question for Adbrite Advertisers about Full Page Ads…

Hi,
I’ve been running different campaigns on adbrite and was wondering if people could give me some feedback about the difference between the
"Target by site quality" options.
The option being:
"Show on preferred sites (sites shown to be more effective)"
or
"Show on all sites (maximize your exposure)"
I’ve always have had my ads set to show on preferred sites when running network ads. I’m wondering though is there really a difference and am I loosing out on good traffic possibilities? Anyone have any experience?
Thanks!

Original post by DonMecca