This site uses an imagemap. Imagemaps are pictures that have clickable objects inside of them. These objects will lead you to various other articles with more information about the object.
The memory book contains all the lore pages you have collected. You can access the memory book from the main menu, or by pressing L (by default) in game. Lore pages contain information about the game world and its inhabitants. Each lore page also allows you to see the details of one achievement.