Channels are virtual dividers that separate, filter and isolate content. Channels are like global filters that affect what content users see when working. If a given piece of content is permitted by the Channel's configuration, it can be shown; otherwise, the content is neither findable nor visible in the Content Browser, regardless of the connected user's permissions. Permissions determine which Channels are available to each user. It is possible (and not uncommon) that only a single Channel is accessible to any given user role. Channels are selected using the large drop-down menu just to the right of the Picturepark logo in the Content Browser.
Each Channel has its own Filter configuration. All search, sort, and filters are kept when switching the Channel, even when closing the browser. That information is only kept in your browser session and will be removed with a cache cleanup or when using a different browser.