These days we hear a lot about the accessibility of social networking sites. Some seem to be very accessible, like LinkedIn, some are making progress these days, like Facebook, and others are just not too usable for people with disabilities at all.
The other day I was very happy to find out that the Accessible Twitter site was designed. Twitter is not very inaccessible in general, but it could definitely use some work. In the meantime, you can visit http://www.accessibletwitter.com for a more accessible experience.
The authors of tweets are embedded into headings, so it is much easier to browse through the new ones just by going down the list of headings. Controls related to the tweets are easier to find too, and general page controls are placed into list views. Especially for users of screen readers, it is a much more effective experience.