Zemanta considers bidding requests when they match targeting preferences from you. As you know your audience best, you can rely on targeting options to focus on buying impressions that are useful for you to get quality impressions.
You can set targeting preferences in both ways - by positively targeting online users that match certain conditions and/or excluding some conditions from targeting. When users target a specific type of audience, context, content, or technology, all the others from the same type are automatically excluded.
For example: If you set up a campaign and add an ad group in which ads are in the Slovenian language, you will probably want to set the location targeting to Slovenia. Zemanta will consider this targeting option and deliver ads only to online users that are located in Slovenia, and not to users anywhere else in the world. On the other hand, if you want to target the whole world but exclude some countries from targeting, excluding logic is recommended for achieving that. This way you will deliberately exclude specific groups of online users from targeting.
Targeting options are available on the Ad Group level under a section named Targeting. All targeting options are disabled by default and you should start adding targeting options by clicking on the + Add button located next to each targeting option. If you change your mind regarding specific targeting that you have added already, you can remove it by clicking on the - Remove button.