CSS Vendor Prefixes

As each browser implements new CSS standards, each publisher interprets these differently. In the past (and present for that matter) designers and coders have been using hacks to hide code from one browser, or to appeal to another directly. CSS3 vendor prefixes will render hacks a thing of the past, as coders will be able to target a browser in the line of code. Later, when browser revisions are released, these prefixes will be dropped in favour of the standard, though the prefixes will remain so we won't have to rewrite our existing code.

For more on this head over to Eric Meyer's article on the A List Apart website, for a thorough and extremely interesting disection of the topic.