Blackboard's rep is claiming certification from the National Federation of the Blind. Is Moodle certified? How can I counter?
Moodle is accesible to the blind. I have worked with a blind student using a screen reader and braile note system to access our school Moodle. The biggest accesibility problems come when teachers don't design courses with clearly defined headers and captions, or when there is a lot of flash in the course. The Moodle platform itself is fairly easy to navigate with a screen reader.
As for how to counter the statement, I looked at the NFB website and this is the list of all the sites that have paid NFB to review and approve their site. It is very small and many sites that are not on their list are highly accesible. I am not sure if Moodle has asked for independant certification of accessibility. http://secure.nfb.org/nfbnva/public/certifiedsites.aspx
According to the forum thread below Moodle developers have focused on accesibility since 1.8 and Moodle code meets Web Content Accesibility Guidelines
http://moodle.org/mod/forum/discuss.php?d=127807
An independant study found that even though Moodle is accesibile there are some places Moodle could be improved. This thread shows the developers interest in the study and their focus on making the improvements. http://moodle.org/mod/forum/discuss.php?d=134143