I think that not only Media Queries should be mentioned but also more general mechanisms for selecting content, such as DISelect [1]
How do you envision DISelect would be used within the widget work? I've not come across any widget engines that make use of DISelect (or any browsers for that matter).
[1] http://www.w3.org/TR/cselection/ --
Marcos Caceres http://datadriven.com.au
