“Sometimes developers use quirks of HTML to improve layout, design, etc,” Ronald Schmelzer, analyst with Waltham, Mass.-based XML consulting firm ZapThink, wrote in an e-mail interview. “XHTML doesn’t tolerate deviations from the specification, making it a bit more rigid as well as complex. What will be the challenge for XHTML is getting HTML designers to think like programmers–not an easy task.”

Read more at: CNet