Optimizely Content Recommendations uses metadata for the following two main purposes:
Within _flows_ as a way to categorize content, based on common metadata attributes. See [Setting up sections and flows](🔗).
Within _rendering_ to specify what elements to display for each content item recommended.
Optimizely recommends the following metadata fields and will support the majority of content recommendation use cases:
**Title** – Title should appear under the meta property **og:title** in the follow format.
**Description** – Description should appear under the meta property **og:description** in the following format.
**Image** – Image should appear under the meta property **og:image** in the following format.
**Published date** – Published date should appear under the meta property **article:published\_time** in the exact format below.
**Article category** – Article category should appear under the meta property **article:category** in the following format.

Additional metadata fields are also supported using the custom namespace (**idio:**) to pass information. For example:
If you have multiple values for a metadata item, Content recommendations collects them all. For example: