Either if you are applying your digital media budget on your own (e.g. Facebook) or if you are using a multinational media agency: You should define your budget split in categories that make sense and enable you to compare spendings and results between in an easy way.
When it comes to definition of the sources where to split your budget, the (digital) media industry has created their own vocabulary and sometimes it can be misleading. On top of that they are influenced by the margins they get from their vendors and media sources – so question their studies and advice.
Here is one approach you can to define the categories of your digital media sources with that will make your life easier: