My email this morning brought me a report of a broken link on our web site. Which I investigated, and found to be within a blog entry I had written a year ago, and linked to someone else's site over which I have no control.

I'm a great believer in providing a wide range of linked resources for our customers, and for other visitors to our web site. With links to sites that we manage (and there are lots of them, from our company overview microsite to Save the Train and from our PHP course pages through to image reuse details via the hotel and the First Great Western customer page), I know how likely (or otherwise) it is that the URLs will go away or change in the future (and can link accordingly), but with most external sites, the best I can do is make an educated guess!

This is not an exact science ... so what can I suggest?

a) That links to the major pages of well established organisations are likely to remain substantially correct, as are links to pages that one's encouraged to link to

b) That links by IP address, to obscure URLs especially within blogs, forums and wikis, are likely to go out of date

It's regrettable that there's no way that you can register any links you add and get the people to whom you've linked to let you know when they take pages away ... but the good ones will replace pages they remove with "301" redirects rather than just abandoning you - as I found this morning - to a "404" not found.

There's another option. You can write a spider / script that will visit all the pages to which you have provided links from time to time, and update you on their status. I have one of these somewhere in a dusty directory - written in Perl and using the LWP module, it trawled my own pages for external references, then visited each of those internal references in turn. But I admit - it's years since I've looked back at it and I need a month of Sundays to catch up on such things.

My current view is that external links within my main pages are very carefully selected, and will rarely go out of date - and I would typically know very quickly. External links on blog articles and on forum answers - well - the reasonable person may expect them to go out of date over time, especially if they're something like an advert for an event in July!



(written 2008-05-04 08:50:01)

 W503 - Web and Intranet - Hypertext
G902 - Well House Consultants - Web site techniques, utility and visibility

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To provide external links, or not?
A short introduction to our courses
Gant charts - drawing them with a PHP script
Amazing family members
Early May - a short chance to regroup and improve
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This is a page archived from The Horse's Mouth at http://www.wellho.net/horse/ - the diary and writings of Graham Ellis. Every attempt was made to provide current information at the time the page was written, but things do move forward in our business - new software releases, price changes, new techniques. Please check back via our main site for current courses, prices, versions, etc - any mention of a price in "The Horse's Mouth" cannot be taken as an offer to supply at that price.

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