Accessibility can work in a number of ways, either through active involvement by a user choosing certain options on the site, or passively without direct user interaction through good site design, color palette selection and similar. Where active involvement by a user is required, this may be achieved either with them making a conscious choice at the time of using a site, or they may already have made a selection (e.g. choice of browser, screen resolution, use of screen reader) which is communicated to the site at the time of use. For users with disabilities, the availability of appropriate and useable accessibility options may mean the difference between them being able to use a site, or looking elsewhere.
How this overlaps with privacy may not be immediately obvious. Privacy refers to the amount of control that we have over our personal information, and how this is shared and used. On the Internet, Privacy can be taken to mean that you are aware of the information that you are sharing, and this information is used in a way that you are comfortable with until it is destroyed.
Browser Information Leakage
So how can accessibility compromise privacy? By knowing that a user is visually impaired, and combining that information with other information, for example that they are located in a certain area (from their IP address, or GPS or other location), you could compromise an individual’s privacy. Research has already indicated that between 63% and 87% of Americans can be uniquely identified by birth date, gender and 5-digit zip code (see here and here for the research and here for some analysis by the Electronic Freedom Foundation). If you’re not convinced – check out the Panopticlick “browser fingerprinter”, also from the EFF. When I just tested my browser, its fingerprint was unique amongst nearly 800,000 configurations tested so far.
Logon Information Leakage
Other accessibility options, such as reading text aloud, may be appropriate for an application being used at home, but may impact privacy if they are used in a location such as a library or a bank lobby, or may not even work if the appropriate hardware is not in place. Developers must give thought to where a website may be used when developing privacy options, particularly when the website grants access to sensitive information.
How Privacy can impact Accessibility
Restrictions on sharing information about people’s health and health conditions may impact the ability to plan appropriately accessible services for them. As a result, companies may not have the information that they need to know how to adapt their sites to their user base, reducing their ability to provide accessible information for all.
While none of these issues are insurmountable, the fast evolving fields of Accessibility and Privacy mean that practitioners must be conscious of these areas when designing new applications as in many places there is no standard for managing the overlap of these two fields.