Dead link
A dead link or broken link is a hyperlink in an HTML document that points to a missing or incorrect URL. Dead links are commonplace on the world wide web, but they are considered to be unprofessional.[1]
Causes
In some cases, a dead link points to a page that consistently changes. This is often the case when a website links to the front page of a blog. Once more posts have been made to the blog, the blog post that the dead link refers to can no longer be found on the blog's front page. A permalink avoids this by linking specifically to the blog post.
Dead links persist because people creating or updating a webpage sometimes copy outdated content from other sites without making sure the links work, or because website administrators do not double-check their older content to insure that the links still work.[2] There are free tools that use web crawlers to recursively check all the links on a website and insure that they still exist.
Symptoms of a dead link
A dead or broken link may have some of the following symptoms:
- If a page has been updated, it is possible the desired content has been removed in favor of new content
- If the broken link points to a functioning web server but the page it links to is missing or has been moved, the user sees a 404 error.
- Alternatively, if the page was deliberately removed by the webmaster, the user might see an explanation.
- If the link returns a DNS error, then no web server is registered with that domain name. This suggests the web site has been closed down, or has switched names.
- When a website's domain registration expires, the domain name is sometimes registered by others in order to serve ads to people looking for the old site. Additionally, some groups try to make use of the PageRank accumulated by being the target of the dead links.
Link rot
"Link rot" is the process by which links on a website gradually become dead as time goes on.[3] A study of science education sites suggests that the half life of a collection of links is 5 years [4]
References
- ↑ Web Tool May Banish Broken Links. BBC News, September 24, 2004. Accessed 01-18-07
- ↑ Broken Links are Bad News for Webmasters. Philip Nicosia, May 25th, 2006
- ↑ http://www.usabilityfirst.com/glossary/term_478.txl
- ↑ "Broken Links: Just How Rapidly Do Science Education Hyperlinks Go Extinct?". Markwell, John and Brooks, David W. University of Nebraska, Lincoln, Nebraska. July 24th, 2006.
External links
- W3C LinkChecker - a tool of the w3c to check for broken links