Though the time saved is, admittedly, negligible from the human user's point of view, there is a greater efficiency to the browser's performance. Most modern browsers will function well in what's usually referred to as "quirks" mode, where, in the absence of any on-page information about the kind of HTML they are reading, present a "best guess" rendering of a page. The quirks mode will also forgive many errors in the HTML. Modern browsers installed on your home computer have the luxury of size and power to deal with these errors. When browser technology makes the leap to other appliances it may not have the size and power to be so forgiving. This is where the strict, valid documents demanded by the XHTML standard become important.

XHTML, the standard, was first released back in 2000. Roughly five years later we begin to see major websites revised to use this standard. Even the favorite whipping boy of standards-compliance punditry, Microsoft, presents their primary homepages, msn.com and microsoft.com in XHTML. Standards compliant XHTML sites are still the minority. The reason is simple. When the W3C released the new standard, the rest of the web running on HTML did not cease to function. Nor will the rest of the web, written in various flavors of HTML, cease to function any time soon. Without any pressing need to conform to the new standard, designers continue to use old, familiar methods. There are 2 primary benefits to using XHTML. First is the strict nature of valid XHTML documents. "Valid" documents contain no errors. Documents with no errors can be parsed more easily by a browser.