Let's say you have a content channel for blog posts, and a content channel for sermons. You can group those two content channels together under a single collection, known as a Content Collection. Content collections put the content for those channels in one place, unlocking the ability to search for content across both channels at once. So, if you have a blog post about finances and a sermon about finances, a person could search your content collection for "finances" and find both items. You can add any number of content channels to your collection, as well as calendars.