Digital Media Access Group

Technical Reasons
You should also consider that:

Your site will be more easily and accurately indexed by search engines - and therefore more easily found by visitors (and potential customers) if good accessibility techniques are applied.
Your web server will run more efficiently if your site is designed with accessibility in mind - as information is easier to find, users will need fewer page requests in order to find what they need. Judicious use of images and multimedia on web pages will help conserve server load.

Your site will be more accessible to users who use the latest technology to access your site (Personal Digital Assistants, TV-based web browsing systems, in-car browsing systems). The chances are that these are users who may have a large disposable income - who may be ready to spend at your site.

By making judicious use of W3C technologies which promote accessibility, such as Cascading Style Sheets (CSS), Extensible Mark-up Language (XML), Scalable Vector Graphics (SVG), Synchronised Multimedia Integration Language (SMIL), and Extensible Style Language (XSL), you develop sites which are future looking, but will also 'degrade gracefully' - i.e. will still be accessible to users of older browing technology.

Legal Reasons
The information on this page is specifically oriented to UK Law.

Disability Discrimination Act
Under the UK's Disability Discrimination Act (DDA) it may be illegal for you to include information on your site which is inaccessible to certain users.

In October of 1999, the DDA was extended to cover all "Goods, facilities and services" to all customers of businesses in the UK.

This means that any organisations who provide information on a web site which is inaccessible to some users, will be liable to legal action.

Education was originally excluded from the DDA. However, this exclusion was removed in 2001, with the introduction of the Special Educational Needs and Disability Act (SENDA)