[I] am concerned to read the report, Collateral Damage in the War Against Online Harms, published last week by Top10VPN and the Open Rights Group, suggesting that these filters are potentially harmful rather than advantageous.

– Baroness Howe of Idlicote (House of Lords Debate, 30 April 2019)

Report cited by:

This week, a new report co-authored by myself has been launched which investigates data collected by the Open Rights Group as part of their Blocked.org.uk project, and highlights a number of concerning flaws in many ISP implementations of adult content filters.

The Blocked! project was designed to help inform users whether particular sites are filtered by UK adult content filters, which our research estimaes to be enabled for around 3.7 million households. Since 2014, Blocked! has collected results from over 35 million website tests and indexed over 760,000 blocked unique domains, with 90% of that data collected since March 2017.

As one of the main authors of the report, I found myself surprised by some of the statistics and patterns which we uncovered during its production. Most obvious is the fact that many of the sites which are blocked are clearly innocuous, and some are downright damaging to filter - such as those related to suicide prevention, LGBT+ rights, or the 34 .sch.uk domains (registerable only by schools) which we found to be blocked at some point during the lifetime of the Blocked! project.

Less obviously, some interesting patterns begin to appear when looking at how the Blocked! project’s user demographic has changed over time. In the early days of the project, many users were, perhaps predictably, activists and Open Rights Group members with an interest in filtering technology. More recently, however, an increasingly large proportion of the site’s userbase is made up of site owners and administrators themselves. Many of these site owners and administrators have directly referenced their belief that the blocking of their websites has led to a real-world loss of business for them.

ISP-level adult content filters are a blunt and inaccurate tool and it was inevitable that serious problems would be uncovered after their implementation. This report highlights some of these problems clearly and suggests a number of recommendations to assist in solving them.

The Top10VPN summary of the report can be read on the Top10VPN site here.

The full 92-page report is also available as a PDF here.