The Backlinks Page
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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/ |
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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.
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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.)
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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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