…or is it easier to ask how long is a piece of string?

The statistic much banded about (for Web pages not pieces of string!) is 44 days, believed to originate in an article by Brewster Kahle (of Internet Archive fame) published in 1997 and titled Preserving the Internet. Brewster’s original quote is specifically about URLs, “…estimates put the average lifetime for a URL at 44 days.”

Whether this figure still stands today is a matter currently being discussed on the CURATORS@LIST.NETPRESERVE.ORG list after a query from Abigail Grotke of the Library of Congress.

Abbie offered up the 44 day statistic and pointed out that on the Digital Preservation Web site they have a graphic that discusses Web volatility stating “44% of the sites available on the internet in 1998 had vanished one year later“.

The other figure often cited is 75 days from a Michael Day’s report Collecting and preserving the world wide web.

“The dynamic nature of the Web means that pages and whole sites are continually evolving, meaning that pages are frequently changed or deleted. Alexa Internet once estimated that Web pages disappear after an average time of 75 days. (Lawrence, et al.,2001, p. 30).“

Another figure sometimes suggested is 100 days, this seems to come from Rick Weiss article for the The Washington Post, Washington, DC, 24 November 2003, On the Web, Research Work Proves Ephemeral -  no longer available.

So what is the average lifespan of a Web page today? Is it getting shorter or longer? The Internet Archive now gives 44 -75 days as its ball park figure. I’d have to hazard a guess that with the rise in use of Web 2.0 technologies the Web is actually getting more transient by the day.

Is this OK?

Maybe if it’s just a tweet you sent your friend, however if it’s something more substantial that’s disapearing then it’s a real worry.