1. make cards "public" (if desired), so that Recall users could search tags, find cards from other users that are useful, and choose to include that card in their personal collection.
  2. Follow other users - if I'm interested in raising rabbits as pets, for example, and there's another Recall user who has the same interest and has a collection of useful cards on pet rabbits, I'd like to be notified when they add a new card.
I think these features would expand Recall's utility from a store of knowledge and organizer of knowledge to also become a source of knowledge. This would also help build community and platform loyalty. -- From Bacon