Site-Targeting issues since after maintence last night

I recently started site-targeting on some heavily viewed
sites but the
ads stop showing shortly after 9pm PST last night after
running pretty
solid for 260,000 impressions (I was monitoring it all
day/night). Now
there are public service ads running instead, no matter how
much I
raise my CPM.

Do anyone have this problem, or know if it has anything to
do with the
scheduled maintence on Adwords last night?

The ads were approved before going live, so maybe an
impression limit,
or it could just be the site owner was tiring of see my ad
up there for
so long. Does Google dedicate a certain amount of time or
impressions
to public service ads?

-Ryan