1. A method performed by a computer system, the method comprising: selecting, using one or more processors associated with the computer system, a first document; representing, using one or more processors associated with the computer system, a first relationship between the first document and a second document as a first link between the first document and the second document, where the first relationship includes at least one of: the first document and the second document sharing a same hierarchical user-defined label, the first document and the second document being associated with a same sub-directory, or the first document and the second document being associated with a same bookmark folder; representing, using one or more processors associated with the computer system, a second relationship between the first document and a third document as a second link between the first document and a third document, where the second relationship includes at least one of: a hierarchical user-defined label associated with the first document and a hierarchical user-defined label associated with the third document being sibling labels, a sub-directory associated with the first document and a sub-directory associated with the third document being sibling sub-directories, or a bookmark folder associated with the first document and a bookmark folder associated with the third document being sibling bookmark folders; and assigning, using one or more processors associated with the computer system, a rank score to the first document based on the first link and based on the second link, where the first link contributes more to the rank score than the second link.