Web Standards - PAGE 4
Faster download speeds
By striping out messy, invalid HTML tags, file sizes can be reduced dramatically. This means that they will load faster, providing your users with a better experience.
Better Accessibility
Sites that keep the structure separate from the content make it easier for screen readers and other devices to interpret your site. Many users of the Internet have some kind of disability so its important your site does not neglect them. From 1st October 1999 The Disability Discrimination Act came into force stating that "service provider has to take reasonable steps to change a practice which makes it unreasonably difficult for disabled people to make use of its services". You can even be sued if your website does not cater for disabled users. By desiging withW3C accessibility guidelines in mind, you can be sure that disabled users will be able to use your website.