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  Update: The CritSuite Toolset Project has been completed. This page is now part of an archive of CritSuite web pages. The domain http://crit.org no longer belongs to this project or to Foresight Institute. For current information on CritSuite, please see the site maintained by the author of the software, Ka-Ping Yee:
http://zesty.ca/crit
 
  Enhancing the World Wide Web: Social Software for the Evolution of Knowledge  

The Backlinks Page

Web Enhancement Project


  Update: The Web Enhancement group has since produced Crit, a web-based service enabling annotation and backlinking on any public web page. Try it out and obtain the software at http://crit.org/  

Last update of content 17Jun97.

"How can you have
an intelligent conversation
if there is no way to reply?" -- TK

This is a quick and dirty attempt to enable backlinks on the web. We want a way to discover all the links pointing INTO a given page on the web. Alta Vista, the wonderful search engine from DEC, collects and indexes the links that appear in web pages. It takes every URL (universal resource locator) that it finds in any web page and puts it in a searchable index.

One simple way to get universal backlinks would be for the browser itself to know how to fetch them from AltaVista. A simple button at the top of the browser would fetch the backlinks to the page you were just looking at. We certainly hope that increased knowledge about the importance of backlinks will convince Netscape and others to create such a button.

Backlinks for Netscape 2.0.x This page from Ted Kaehler lets you see the backlinks to any page. Go to this page at the start of your browsing session. Follow the directions and let it create the window for you to browse in. Whenever you want backlinks, click in the original page, and click "Links to Other Page". This launches an AltaVista search for links to the page you were just looking at. It only works with Netscape 2.0.x. The technique it uses has been outlawed in Netscape 3.0.x.

However, a fix for this problem was recently discovered by Ka-Ping Yee so that it can be made to work in Netscape 3 as well.

Robin Hanson's FindCritics page An excellent discussion of how to make criticism possible and easy on the web. A comprehensive summary of the known ways to get the capability for backlinks. One way that Robin has pioneered, is to include a built-in backlinks button on your page.

known by AltaVista

known by Open Text Index

Those only work if your browser understands JavaScript. See below for hardwired backlinks buttons. They have the URL of the page written right into the html.

Tim Freeman's Backlink Script automatically put a "Backlinks" button on the bottom of every page. He does this by fetching pages for you, processing them, and then passing them on to your browser. Needless to say, if every one used Tim's service, his machine would be swamped. But give it a try as an exciting look at what will be possible someday. Click on this:

A Backlinks button on every page

As long as you only click on URLs in pages, the backlinks button will stay at the bottom. Don't use bookmarks or paste URLs in the location box. Slow, because every page goes through Tim's machine.

You can, in fact, paste in any URL and still get a backlinks button via Tim's script. Put this text in front of the URL you want:

http://www.best.com/~timothy/cgi/blnk/backlink.cgi/
For example:
http://www.best.com/~timothy/cgi/blnk/backlink.cgi/http://www.foresight.org/
Another one he has set up:
http://www.infoscreen.com/cgi/blnk/backlink.cgi/

Open Issues

The reason that Ted Kaehler's "Backlinks for Netscape 2.0.x" won't work in 3.0 is because reaching into another window is a security violation. Ted's script holds a reference to the other browser window, and when you press the button, it asks the other window for its URL. If Netscape allowed this, you could make a normal web page that kept a log of everywhere you went after you looked at it.

Perhaps there is a way to enable backlink buttons without opening a larger security hole. We should explore this with the browser companies, in addition to asking for a Backlinks button.

Full Java currently allows the programmer to get at the history list. A backlinks page that included a Java Applet would look just like Ted's page with two buttons. You create another window and browse in it. When you want backlinks, click "Links to Other Page." Java reaches into the history list or into the other window to find out where you just were. It constructs the query and sends it off. (This more or less defeats the security introduced in 3.0. If they find out and fix it, this too will cease to work.)

Note, however, a fix for this problem was recently discovered by Ka-Ping Yee so that it can be made to work in Netscape 3 as well.

Another approach is to use a CGI script on a specific server to construct the query. Servers running CGI have access to the HTTP_REFERRER variable. It contains the URL of the last page you were at. Here is how it looks to the user: You have a bookmark to the "Backlinks" page that lives on a CGI capable server. You browse the web until you see a page you want backlinks to. Choose "Backlinks" from the bookmarks. When you get to the server, it collects the previous URL, constructs an AltaVista query, and sends the results back to you. The server gets out of the loop after the query, so one machine would be able to serve many users. Does anyone want to volunteer to write such a CGI script?

Here are some hardwired buttons you can modify and include on your own page. These will work with any browser. (The ones above required JavaScript.)

known by AltaVista

known by Open Text Index


Contact: Chris Peterson, phone 415-917-1122, email foresight@foresight.org
This page by Ted Kaehler.

References
"The Network of Knowledge," chapter 14 of Engines of Creation by K. Eric Drexler (Anchor Press/Doubleday, 1986). The Notes give earlier references.



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