10. A non-transitory computer-readable storage medium having instructions stored thereon that, when executed by a processor, cause the processor to perform operations comprising: receiving an image of a portion of a document that was captured by a first user using a camera, wherein the image includes text; identifying an electronic document that includes the text; determining, by the one or more computing devices, that there are a plurality of versions related to the identified electronic document, wherein the plurality of versions of the electronic document include a first version that corresponds to the document and a second version that differs from the first version; and providing, in response to the determination, data that present document information informing the first user of the plurality of versions of the electronic document together with information identifying, to the first user, a second user that is currently reading a most recent version of the document.
10. A non-transitory computer-readable storage medium having instructions stored thereon that, when executed by a processor, cause the processor to perform operations comprising: receiving an image of a portion of a document that was captured by a first user using a camera, wherein the image includes text; identifying an electronic document that includes the text; determining, by the one or more computing devices, that there are a plurality of versions related to the identified electronic document, wherein the plurality of versions of the electronic document include a first version that corresponds to the document and a second version that differs from the first version; and providing, in response to the determination, data that present document information informing the first user of the plurality of versions of the electronic document together with information identifying, to the first user, a second user that is currently reading a most recent version of the document. 11. The non-transitory computer-readable storage medium of claim 10 , wherein the second version of the electronic document is derived from the first version of the electronic document.