The Hauptman article, discusses the reasons for documentation.  I think two of the more important reasons for documentation are for acknowledgement and attribution. It is important to acknowledge where you retrieved a certain idea and to attribute it to its creator. In the Bugeja & Dimitrova article, they discuss research in which they try to determine that factors that affect online footnote/citation permanence. Many of the factors have to do with updates and restructuring that lose footnotes in the process. In the example of footnotes that link out to other pages, if the URL is too long, someone creates a new folder to place similar content and produces a failed footnote. It would make more senses to leave a footnote unchanged but over time it can turn out unusable because the web page might be heavily changed or deleted altogether.