1. A method performed by one or more server devices, comprising: receiving, using a processor of the one or more server devices, a comment associated with a first document, the comment corresponding to a portion of the first document; determining, using a processor of the one or more server devices, that a size of the portion of the first document is greater than a threshold size; identifying, using a processor of the one or more server devices, one or more second documents when the size of the portion of the first document is greater than the threshold size, where each of the one or more second documents includes a portion that matches the portion of the first document; storing, in a memory associated with the one or more server devices, the comment in association with the first document and the one or more second documents; and presenting, using a processor of the one or more server devices, the comment in connection with one of the one or more second documents when the one of the one or more second documents is accessed by a user.