This listing of the nubmer of ad spots each
candidate has run is an eye opener. Notice Huckabee isn't even on
the list. To Phil's point, it also may explain Rudy's December. If
you are invisible on the air, you're not going to hold your own in
the polls for very long. (Even Ron Paul is ahead of him in ad
spots.) At some point there must be diminishing returns (the
18,000th ad for Romney doesn't have as much impact as the first few
thousand, I would imagine) but it suggests that Huckabee and others
may still have room to boost their recognition and appeal.