On the other hand, what other factors go into a campaign's ad-buying decision?  For example, does Bush think the organization that Jeb and the Repubs have in FLA is good enough that he doesn't need to go hog wild on ads?  I'd expect the expense of air time would have an impact, too. I'd guess it's a lot cheaper in Iowa than it is in Miami or Philadelphia.  

What other factors go into the decision?

My sense is that Edwards helps Kerry more than Gep everywhere except Mo, and maybe even in Mo too.

Considering Iowa has at least 4 media markets (Ames, Des Moines, Iowa City, Dubuque) plus several however many smaller towns have seperate markets (Quad Cities? Waterloo?), I think it's quite plausible that Ohioans and Floridians are seeing more ads.

I'm not sure what the right measurement is. I think it's something like showings per station per electoral vote. So if you buy 20 spots in Tampa and 10 spots in Florida, you get 15 showings / 27 electoral votes.

here's an interesting site for anyone
looking at the TV race.  (it's a little dated,
based on proprietary info apparently
released in a court case).

one obvious problem is that for full
coverage, stations outside a state figure in.

since we are Democrats, we usually
don't have enough money to buy
these secondary stations.

to completely cover Arkansas, for
example, you'd have to buy Memphis --
very expensive -- and Greenville, Miss.

or just give up on reaching rural and
small town voters along the Mississippi
River. (oh, have we done that in the past?)

to reach into southwest Virginia you
need to buy the Tri-Cities of
Bristol-Kingsport-JohnsonCity
in northeast Tenn.

but if the campaign decided to make
a fight in Teneessee, for example,
we'd get part of Arkansas and Virginia
"free" -- not to mention parts of Mississippi
and Kentucky too.

but nothing is free. TV is costly, and
there's the rub.