Given the discussion at Web Directions South this year regarding the relationship between usability and accessibility, this conference should prove popular:
UA Web 2008, Monterey, Mexico
The International Seminar on Usability and Accessibility for the Web will have Jesse James Garrett as the Keynote speaker and José Manuel Alonso, representing the e-Government chapter of the W3C will also speak. Together we will explore current trends in usability, accessibility, strategy, innovation, user experience and web standards.
