A Web Accessibility Service: Update and Findings
Vicki L. Hanson, John T. Richards · 2004 · Proceedings of the 6th International ACM SIGACCESS Conference on Computers and Accessibility (Assets 04) · doi:10.1145/1028630.1028661
Summary
This paper reports on the evolution of IBM's Web Accessibility Service from a proxy server prototype (presented at Assets 2002) to a client-side architecture that transforms web pages on the fly to meet the needs of older adults and people with disabilities. The original proxy approach intercepted HTTP requests and modified content before delivering it to the browser, but field testing revealed serious problems: secure (SSL) sites could not be proxied without breaking the trust chain, the proxy could not accurately render pages the way browsers did, and the system could not scale to handle many simultaneous users. The revised architecture moves all transformations to the client machine using a Browser Helper Object (BHO) for Internet Explorer that manipulates the Document Object Model (DOM) after the browser renders the page. This approach eliminates the proxy entirely — the server only stores user preferences in an LDAP/DB2 database. Visual transformations include changing colors, font sizes, line spacing, letter spacing, image enlargement, page linearization (converting multi-column layouts to single column), hiding images, stopping animations, and removing background images. The system also integrates IBM's Dynamic Keyboard for automatic keyboard accessibility adjustments and IBM ViaVoice for text-to-speech, where users can hover over text or images to hear content read aloud. The software was translated into six languages and deployed to organizations serving older adults, people with disabilities, students with learning disabilities, and speakers of English as a second language.
Key findings
After a year of deployment with several thousand users, usage data revealed clear patterns in which adaptations were most valued. The speak text feature (text-to-speech on hover) was used by approximately 41% of users, proving particularly popular among low vision users as reinforcement while reading and among low literacy individuals. Text size enlargement was also used by about 41% of users, with the majority choosing the smallest magnification level, suggesting that modest increases in text and page size were sufficient for most. Text style and color contrast changes were used by over 30% of users. Banner text, image enlargement, and browser control enlargement were each used by about a quarter of users. Less popular features included line spacing, letter spacing, and stopping animations (10-20%), while hiding images and backgrounds was used by only 10%. The concept of "dynamic diversity" emerged as a key design insight: older adults have complex, intersecting, and fluctuating needs that change from day to day and even within sessions due to fatigue. This means a "one size fits all" approach is inadequate, and the system must provide flexibility for users to easily combine multiple adaptations.
Relevance
This research is significant for accessibility practitioners because it articulates the distinction between web accessibility (making pages technically conformant to standards) and web usability (making pages actually usable by diverse populations). The authors argue their tool complements rather than replaces WCAG compliance: even pages that meet accessibility standards may still be difficult for many users, particularly older adults with multiple mild impairments. The finding that 41% of users adopted text-to-speech validates the value of multimodal content delivery even for sighted users. The client-side architecture that emerged from the failed proxy approach anticipated the modern model of browser extensions for accessibility. The concept of dynamic diversity — that users' needs are not static but fluctuate based on fatigue, medication, time of day, and other factors — remains highly relevant for designing adaptive accessibility solutions. A key limitation is that the system was Internet Explorer-specific and dependent on proprietary IBM technologies, limiting its broader applicability, though the design principles transfer well.
Tags: web accessibility · web adaptation · aging · assistive technology · personalization · content adaptation · browser accessibility · user interface · web transcoding
Standards referenced: WCAG 1.0 · Section 508 · User Agent Accessibility Guidelines