Each placement on a site is defined into subcategories – for example, finance, technology, society, family, fashion, news. These subcategories are called placement groups in smartx. These placement groups allow for the categorisation of inventory into very granular subgroups, facilitating precise targeting on the demand side.
Placement groups from different publishers can be combined within content channels to bundle similar content (for example, news, politics, or based on IAB categories).
See also Content Channel and Sites.