As I hightlighted some time ago, XHTML 2.0 introduces a
media attribute. Although you can use it effectively there are potentional pittfalls as Faruk Ateş points out:
A much greater threat arises when Google starts indexing content for
media="print", which may contain nothing but a large amount of generic search terms, and using that index in their search results.
It’s basically the same as
display:none on some
div element except that this looks more trustful at start.