1. A system for collaborative generation of a plurality of customized documents, each comprising a plurality of text passages, the system comprising: a server connected to a network for maintaining storage of a plurality of text passages in a database; and at least one networked client computer in communication with the server and configured to receive user input from an author for generating documents comprising a plurality of text passages by at least one of (i) generating new text passages, (ii) selecting already-generated text passages authored by others, and (iii) modifying already-generated text passages, wherein different authors are responsible for generating different documents and different text passages, and wherein the server is configured such that: when a new text passage is generated for inclusion in a document, the server stores the new text passage in the database and creates a link of a first type between the new text passage and the document, and when an already-generated text passage is selected for a document, the server creates a link of a second type between the selected text passage and the document, wherein the first type of link is a static copy link, and the second type of link is selectable by the author of the document to be either a static or dynamic copy link; and when a text passage having a link of the first type to a first document is being modified for the first document, and the text passage also has a link of the second type as a static copy link to a second document, the server breaks the existing link of the first type, stores a different text passage containing the text passage in its modified form, and creates a link of the first type between the different text passage and the first document, wherein the second document maintains the static copy link to the original text passage without the modifications.