Live Font Interpolation on the Web
An A List Apart article on the opportunities of responsive typography.
The article covers some of the challenges inherent in responsive design (essentially designing for a lot of contexts in general) and how type should scale and be treated as a first class design element. It explains the benefits of being able to interpolate type on the fly in order to adapt to users and shows some examples in how people can get started.
The articles proof of concept lives here.