In early 2007 when Yahoo Panama was officially launched, its geo-targeting feature came automatically with a map for advertisers to opt-out regions or countries in which they do not want their ads to be shown. Recently, Google implemented its Maps services into the location targeting feature of Adwords.
Honestly, with a visual map in front of you it requires less efforts in selecting the locations / regions to do geo-targeting.
Adwords has always been a more scalable PPC platform than Panama mainly because it enables advertisers to randomly select multiple countries and/or regions to geo-target. Panama, on the other hand, still requires advertisers to create one account per country before they are able to run campaigns across multiple countries.