Pinning a post is one of the easiest and most effective ways to ensure that your most important post is the first thing that visitors of your community will see. It allow you to draw attention to a certain piece of content of your community. 

You can pin just any content in your community. Think of a pinned post as a sort of “preview” of your community. While your most recent content might not make the greatest impression of your community, a pinned post has the potential to do that.

In Tribe, admins can pin any content, including questions, posts, discussion, and articles. A pinned post will stay at the top of your home feed and/or a group page

Right now, the order of showing the pinned posts is based on the time they are pinned. Later on, we are adding the option to change the order of pinned posts much more easier.