More information from in-game descriptions and from the Encyclopedia.
Here's a scenario: I have a quest that requires plain bubbles; I ended up with some in my inventory from my first day but now I can't remember how I got them. Maybe I can find information by searching the forum, but the Encyclopedia is no help. It tells me very little about items — most notably, where to find them/how to get them. Then, if I discover that they come from interacting with a Bubble Tree, I then have to search all over on where to find a Bubble Tree. In other words, there is no encyclopedia entry for types of trees, or other in-world objects, only for objects which the character can pickup. Maybe the point here is to get players to walk all over giant's creation to find one object, or to get lots of in-game chatter, but some player's may not want that...even in a 'social' game.