Accessibility

On the back of the current lesson - it'd be quite nice to have a lesson or two on some of the basic things we dev's can do to make our sites more accessible.

I know from my own work that even things like "big" projects like Twitter Bootstrap fail a lot of the guidelines, but I've very little idea about all the html/css stuff that's appeared over the past couple of years to help people use sites with screen-readers etc. I know vague things like there's an 'aria' thing and 'role=', but I think it'd be nice - actually more than 'nice' - to see more emphasis on it. Especially on the back of adding more and more JS/components to our pages :-)