Idea: Attributes to documents so we can show that in the feed instead of the whole document

Like @gabo mentioned a few months back, having special attributes in documents like "Summary" or "Abstract" could be interesting so we can use that information for the Feed items instead of rendering the whole document.
This came to me because the feed view felt similar to the X timeline. and when someone shares a post there, they add a little description in the tweet with the link to the content.
I really see this as a part of the publishing process, where we show users a popup and they can add this type of data before publishing. Here's where users can also add categories, publish to multiple groups in one go and have more control over what and how will this document be published.