WCAG, stands for Web Content Accessibility Guidelines (WCAG) and is a set of guidelines used by web designers and developers to help improve the accessibility of their web sites to people with disabilities.

The recommendations in the guidlines are divided into 3 different levels of priority. These are, level A, AA and AAA. People sometimes talk about their site being double A or triple A compliant, referring to the extent to which they have implemented the accessibility guidelines.

WCAG is created by the W3 consortium and has been a controversial set of guidelines. On 3 November 2008, WCAG 2.0 became a W3C Proposed Recommendation which is actually a lot more concrete than it sounds.You can view the full text of WCAG 2.0 on the W3 consortium's website.