The standards of the W3C provided clear guidelines for designers and coders to follow to make sure their sites are widely viewed and assessable from many platforms and also allowing precise visual control.
General Guidelines for great markup include using a DOCTYPE, specifying a language/character set, titling it, using proper elements, avoiding div-itis, minimizing markup, and using class and id appropriately. Using a DOCTYPE helps browsers identify the markup language used for the site. Specifying a language /character set tags your document with a human language which browsers will use to filter through results based on the language used. Titling the document is saved as the link description and is showed in the users browser window and bookmarks. Search engines also use titles as main keywords when generating site traffic. Using proper elements means to markup the document using HTML elements according to the structure of the page content. Avoiding the overuse and misuse of div tags is to not replace more appropriate HTML tags. If a heading tag fits best and describes the content then one should use that instead of a div tag. A div tag should be used more as a reusable, styled container in order to separate sections in a page. Minimizing markup means to only have the necessary tags and elements that make up your page and to trim unneeded markup. This will create a smaller file size and allow it to get onscreen faster. Using class and id properly helps CSS and JavaScript attach correctly to HTML elements. An id can only be used once per page as apposed to a class, which can be reused.
Some benefits of web standards include smaller file sizes and quicker downloads, increased portability, better page accessibility, and having precise control. Having smaller file sizes can happen when you move your markup into CSS. This enables browsers to cache the CSS styles so the page loads quicker. Increased portability happens in the way you format your CSS styles. Without CSS, the basic elements are properly formatted for a mobile version of your site. With CSS, you can format it for many different screen sizes and present it differently according to the sizes. This gives you a bigger window of opportunity to design it according to your target audience. When proper HTML elements are used, the markup is accessible and it will follow 90% of the World Wide Web Consortium content guidelines and be available to a wide audience. CSS allows designers to have precise control on the look and movement of the site.