In spite of excellent support for HTML authors to create printer friendly version of their documents using CSS, many of the documents on the web today look horrible when printed. Even pages that provide a printable view suffer a major flaw. If the documents have links there is no way of knowing where they point to from the physical copy. This has always bugged me. When I have things printed out and there are links in the page that I would have liked to read, going back to the original document and hunting down the links is too much of a hassle. Take this NY Times article in printable view for example, it would be nice If I could after reading this printed page read the link to the avian flu in the article.
Since I use firefox, I wrote a Firefox Greasemonkey userscript that will automatically create references at the end of the printed document for every link in the page. And to make it really easy, the links are tinyurls that allow for easy typing instead of the original long URLs.
Download Printable.user.js after installing the Greasemonkey plugin in Firefox.