19. The non-transitory computer-readable medium of claim 11 , wherein the first electronic document is a word processing file and the second electronic document is a portable document format (PDF) file.
11. A non-transitory computer-readable medium having stored thereon instructions that are executable to cause a computer system to perform operations comprising: opening a first electronic document; creating a second electronic document superimposed over the first electronic document to receive annotations in reference to the first electronic document; creating, in response to creating the second electronic document to receive annotations, an association between the first electronic document and the second electronic document; saving the second document as a separate document independent of the first document; in response to a second opening of the first electronic document, and based upon the association between the first electronic document and the second electronic document that was annotated during a previous viewing of the first electronic document, automatically opening the second electronic document without user intervention; superimposing the second electronic document with the annotations over the first electronic document; and receiving additional annotations in reference to the first electronic document within the second electronic document concurrently while viewing the first electronic document beneath the second electronic document.