Ad placement, overkilled question

I know this has been asked numerous times and the answer to the question:

"Do ads have to be displayed on all pages" is YES

but I have come across ads on our site which have had these ads only placed in a single setion of their website.

Cheers,
Max

 

The have to be on ALL pages WITHIN your base URL.

So you can limit it to a folder or subdomain.

 

But does that mean that you would only get credit (ie weight score) for those google cached pages which fall under that folder / subdomain ?

 

yes it does

 

Makes sense, thanks for the help.

Cheers,
Max