As opposed to mono-directional links we can find on the web. Bi-directional links have an awareness: they know about other pages to point to it, and can make them visible to people.
While having bi-directional links on the web by default can be very challenging (imagine if ill-intentionned people linked to your site), they prove useful in smaller, personal spaces like this one.
- They add context to pages: this breaks the linearity and allows to discover connected things.
- They allow structure to emerge naturally, as opposed to strongly defined taxonomies.