I don't know how complicated it'd be, or if there are any add-ons for it, but you know how motifs tell you if you have a certain page learned? Well, can we get formulas and diagrams to tell us that too? I hate picking up a diagram for a cool piece of furniture thinking "wow I'd love to make this later", only to find out you've already learned it (probably learned it weeks ago, and you don't even remember doing so).