pros and cons of making ad unit targetable

Do advertisers target ad units or whole sites

[denisl]

doing some re-organising of ads and setting up new one - selected for ad to be targetabel.
I don't think I have done this before - I knew a number of important advertisers were targeting my site anyway.

Anyone know, do advertisers like to target individual ad units?

Are there pros and cons for publishers?

[netmeg]

Some advertisers do it; you're more likely to see it when you want to advertise on a larger site, with a lot of different sections (for example, the food section of a large newspaper site, or once I had a music industry client who wanted to advertise on the jazz sections of various music related sites)

I describe my channels, because a lot of my site are based on location and I know some people want to target these locations (specially in an election year) but I haven't quite gotten it down to the ad unit or URL level.