It’s important to understand that most CMSs have a bias. They’re often designed around a certain “unit” of content and that’s what they’re optimized to create. For blog applications, the unit is a post. For Sharepoint, a unit is a document. For most web content management tools a unit is a webpage, even though we’re more likely to be making dynamic sites that use (and reuse) content in a variety of configurations.
Most CMSs, but not all. There are many reasons to love Symphony CMS, but this is one of the easiest for new users to grasp: there are no preconceived notions of content structure, and Symphony makes it dead simple to quickly create a model to match your exact needs. If your CMS is forcing you to use its markup or its data model, it’s doing it wrong.