Linkrot

[Steve]

Fighting Linkrot 

Jakob Nielsen's Alertbox 6/98


6% of the links on the Web are broken according to a recent survey
by Terry Sullivan's All Things Web. Even worse, linkrot in May 1998
was double that found by a similar survey in August 1997. 

Linkrot definitely reduces the usability of the Web, being cited as
one of the biggest problems in using the Web by 60% of the users in
the October 1997 GVU survey. This percentage was up from "only" 50%
in the April 1997 survey. Users get irritated when they attempt to go
somewhere, only to get their reward snatched away at the last moment
by a 404 or other incomprehensible error message. 

Even worse, linkrot contributes to dissolving the very fabric of the
Web: there is a looming danger that the Web will stop being an
interconnected universal hypertext and turn into a set of isolated
info-islands. Anything that reduces the prevalence and usefulness of
cross-site linking is a direct attack on the founding principle of
the Web. 

Most of this danger comes from attempts to use subscriptions instead
of micropayments as a business model, thus erecting barriers to free
navigation. Other dangers come from the craze for "portal" sites
that guide users based on kickbacks instead of customer value: when
links are determined by the size of payments instead of editorial
judgment, users get cheated and benefit less from the Web. This is
not to say that payments can't flow along links; just that these
payments have to be generated by the users. Thus, it is fully ethical
for Amazon.com to pay a commission to referring sites for books that
users buy after following a link: the point is that payment only
happens if the user is satisfied with the link and buys the
recommended book. 

Reducing Outbound Linkrot

Since users are irritated by linkrot, it is in your interest to
reduce the amount of dead links in your own pages. The overall
quality of the user experience strongly influences people's
assessment of the credibility and value of a site: if a site doesn't
work well, users will abandon it. Not only are dead links
disappointing to users, they also rob your users of the value they
were supposed to gain from going to the destination site. Remember,
that one of the main reasons to include outbound links on a site is
that users will credit you with some percentage of the value they
gain from the sites you link to: thus, well-selected links enhance
the value of your own service with the best of all the Internet has
to offer, driving up user loyalty and repeat traffic to your site. 

The standard advice is to run a link validator on your site at
regular intervals. For small sites, it may make sense to outsource
validation to a service that will spider your site maybe once a month
and email back a list of dead links. For larger sites, it is more
cost-effective to install validation software on the server itself.
In either case, you need to have processes in place to contact the
page authors to have them update or remove the offending links. 

Let Incoming Links Live

Any URL that has ever been exposed to the Internet should live
forever: never let any URL die since doing so means that other sites
that link to you will experience linkrot. If these sites are
conscientious, they will eventually update the link, but not all
sites do so. Thus, many potential new users will be met by an error
message the first time they visit your site instead of getting the
valuable content they were expecting. Remember, people follow links
because they want something on your site: the best possible
introduction and more valuable than any advertising for attracting
new customers. 

Sometimes Web content becomes truly obsolete. An example would be
the advance program and registration form for a conference that has
already taken place. In such cases, it makes sense to remove the
original page. Even so, the URL should still be kept alive and
should be redirected to point to either a follow-up message (e.g., a
report from events at the conference) or to a current page that is as
close as possible to the original one (e.g., the program for next
year's conference). 

At other times, it becomes necessary to re-architect a site and
impose a new structure. Even then, the rule continues to be: you are
not allowed to break any old links. The solution is to set up a set
of redirects: a scheme whereby the server tells the browser that the
requested page is to be found at a new URL. All decent browsers will
automatically take the user to the new URL, and really good browsers
will even update their bookmark database to use the new URL in the
future if the user had bookmarked the old URL. 

Any time one of your old URLs stop working, you are throwing away
business. It is like refusing entry to a shop for anybody who is
dressed in last year's fashion. 

Keep all old pages on your server forever (unless they are truly
misleading and are replaced by an update). If moving pages, leave a
redirect behind.




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