Attention web site designers and publishers: according to Jeffrey Zeldman, in a book excerpt from Forward Compatibility: Designing & Building With Standards (2003 publication), we are undermining the success of our sites through flawed markup that slams the door on the metaphorical face of lots of potential users. Zeldman argues for the adoption of web standards developed by the collective World Wide Web Consortium (W3C) as an essential means of ensuring the future accessibility and functionality of web site content.