Pew Research On Link Rot

Source

When Online Content Disappears by Athena Chapekis, Samuel Bestvater, Emma Remy and Gonzalo Rivero reports results from this research:

we collected a random sample of just under 1 million webpages from the archives of Common Crawl, an internet archive service that periodically collects snapshots of the internet as it exists at different points in time. We sampled pages collected by Common Crawl each year from 2013 through 2023 (approximately 90,000 pages per year) and checked to see if those pages still exist today.

We found that 25% of all the pages we collected from 2013 through 2023 were no longer accessible as of October 2023. This figure is the sum of two different types of broken pages: 16% of pages are individually inaccessible but come from an otherwise functional root-level domain; the other 9% are inaccessible because their entire root domain is no longer functional.

Their results are not surprising, but there are a number of surprising things about their report. Below the fold, I explain.

Attacking (Users Of) The Wayback Machine

Right from the start, nearly two decades ago, the LOCKSS system assumed that:

Alas, even libraries have enemies. Governments and corporations have tried to rewrite history. Ideological zealots have tried to suppress research of which they disapprove.

The LOCKSS polling and repair protocol was designed to make it as difficult as possible for even a powerful attacker to change content preserved in a decentralized LOCKSS network, by exploiting excess replication and the lack of a central locus of control.

Just like libraries, Web archives have enemies. Jack Cushman and Ilya Kreymer's (CK) talk at the 2017 Web Archiving Conference identified seven potential vulnerabilities of centralized Web archives that an attacker could exploit to change or destroy content in the archive, or mislead an eventual reader as to the archived content.

Now, Rewriting History: Changing the Archived Web from the Present by Ada Lerner et al (L) identifies four attacks that, without compromising the archive itself, caused browsers using the Internet Archive's Wayback Machine to view pages that look different to the originally archived content. It is important to observe that the title is misleading, and that these attacks are less serious than those that compromise the archive. Problems with replaying archived content are fixable, loss or damage to archived content is not fixable.

Below the fold I examine L's four attacks and relate them to CK's seven vulnerabilities.

Reference Rot Is Worse Than You Think

At the Fall CNI Martin Klein presented a new paper from LANL and the University of Edinburgh, Scholarly Context Adrift: Three out of Four URI References Lead to Changed Content. Shawn Jones, Klein and the co-authors followed on from the earlier work on web-at-large citations from academic papers in Scholarly Context Not Found: One in Five Articles Suffers from Reference Rot, which found:

one out of five STM articles suffering from reference rot, meaning it is impossible to revisit the web context that surrounds them some time after their publication. When only considering STM articles that contain references to web resources, this fraction increases to seven out of ten.

Reference rot comes in two forms:

• Link rot: The resource identified by a URI vanishes from the web. As a result, a URI reference to the resource ceases to provide access to referenced content.
• Content drift: The resource identified by a URI changes over time. The resource’s content evolves and can change to such an extent that it ceases to be representative of the content that was originally referenced.

Source

The British Library's Andy Jackson analyzed the UK Web Archive and found:

I expected the rot rate to be high, but I was shocked by how quickly link rot and content drift come to dominate the scene. 50% of the content is lost after just one year, with more being lost each subsequent year. However, it’s worth noting that the loss rate is not maintained at 50%/year. If it was, the loss rate after two years would be 75% rather than 60%. This indicates there are some islands of stability, and that any broad ‘average lifetime’ for web resources is likely to be a little misleading.

Clearly, the problem is very serious. Below the fold, details on just how serious and discussion of a proposed mitigation.

Improving e-Journal Ingest (among other things)

Herbert Van de Sompel, Michael Nelson and I have a new paper entitled Web Infrastructure to Support e-Journal Preservation (and More) that:

• describes the ways archives ingest e-journal articles,
• shows the areas in which these processes use heuristics, which makes them fallible and expensive to maintain,
• and shows how the use of DOIs, ResourceSync, and Herbert and Michael's "Signposting" proposal could greatly improve these and other processes that need to access e-journal content.

It concludes with a set of recommendations for CrossRef and the e-journal publishers that would be easy to adopt and would not merely improve these processes but also help remedy the deficiencies in the way DOI's are used in practice that were identified in Martin Klein et al's paper in PLoS One entitled Scholarly Context Not Found: One in Five Articles Suffers from Reference Rot, and in Persistent URIs Must Be Used To Be Persistent, presented by Herbert and co-authors to the 25th international world wide web conference.

Signposting the Scholarly Web

At the Fall CNI meeting, Herbert Van de Sompel and Michael Nelson discussed an important paper they had just published in D-Lib, Reminiscing About 15 Years of Interoperability Efforts. The abstract is:

Over the past fifteen years, our perspective on tackling information interoperability problems for web-based scholarship has evolved significantly. In this opinion piece, we look back at three efforts that we have been involved in that aptly illustrate this evolution: OAI-PMH, OAI-ORE, and Memento. Understanding that no interoperability specification is neutral, we attempt to characterize the perspectives and technical toolkits that provided the basis for these endeavors. With that regard, we consider repository-centric and web-centric interoperability perspectives, and the use of a Linked Data or a REST/HATEAOS technology stack, respectively. We also lament the lack of interoperability across nodes that play a role in web-based scholarship, but end on a constructive note with some ideas regarding a possible path forward.

They describe their evolution from OAI-PMH, a custom protocol that used the Web simply as a transport for remote procedue calls, to Memento, which uses only the native capabilities of the Web. They end with a profoundly important proposal they call Signposting the Scholarly Web which, if deployed, would be a really big deal in many areas. Some further details are on GitHub, including this somewhat cryptic use case:

Use case like LOCKSS is the need to answer the question: What are all the components of this work that should be preserved? Follow all rel="describedby" and rel="item" links (potentially multiple levels perhaps through describedby and item).

Below the fold I explain what this means, and why it would be a really big deal for preservation.

A good op-ed on digital preservation

Bina Venkataraman was White House adviser on climate change innovation and is now at the Broad Foundation Institute working on long-term vs. short-term issues. She has a good op-ed piece in Sunday's Boston Globe entitled The race to preserve disappearing data. She and I e-mailed to and fro as she worked on the op-ed, and I'm quoted in it.

Update: Bina's affiliation corrected - my bad.

The Mystery of the Missing Dataset

I was interviewed for an upcoming news article in Nature about the problem of link rot in scientific publications, based on the recent Klein et al paper in PLoS One. The paper is full of great statistical data but, as would be expected in a scientific paper, lacks the personal stories that would improve a news article.

I mentioned the interview over dinner with my step-daughter, who was featured in the very first post to this blog when she was a grad student. She immediately said that her current work is hamstrung by precisely the kind of link rot Klein et al investigated. She is frustrated because the dataset from a widely cited paper has vanished from the Web. Below the fold, a working post that I will update as the search for this dataset continues.