The video, drag-n-drop, canvas and other features promised by HTML5 have drawn much attention, but it's not yet appropriate to build websites against the emerging standard, W3C official cautions. Separately, privacy experts point to open concerns.

Since the early days of HTML, the markup language has been evolving to support richer content and media. To some extent Web content has become a hodgepodge of different standards that attempt to marry text with multimedia. Now that the Web is at the brink of adopting a new standard that promises to support rich content natively without external plug-ins or applications, standards officials warn that the new version of HTML is not yet ready.

Richer Content, Minus the Overhead

The World Wide Web Consortium, or the W3C—the international body that adopts Web standards—has been developing HTML5 since 2004 as a successor to the current HTML 4.01 and XHTML 1.1 standards, upon the initial work of the Web Hypertext Application Technology Working Group (see our HTML5 primer here).

Among the salient features of HTML5 are native support for rich content like video, and UI advancements like drag-and-drop. These are functionalities currently addressed by a mixture of third-party browser plug-ins, such as Adobe Flash and Microsoft Silverlight, and JavaScript libraries like jQuery.

Much excitement has been generated over HTML5, particularly from within the web development community. For example, Apple’s Steve Jobs has touted HTML 5 as a viable replacement for Flash, highlighting Apple’s preference for open standards rather than closed ones.

In particular, Jobs highlighted the disadvantage of Flash when it comes to mobile devices. By adding an additional software layer for decoding, Flash will easily eat up processing power and battery, whereas a hardware-decoded approach like H.264 should improve performance and power efficiency. Industry giants Google and Microsoft are also rooting for HTML5 as a fully-integrated approach to a richer Web experience. Microsoft will be fully implementing HTML5 in its upcoming Internet Explorer 9. Google, meanwhile, has been deploying certain HTML5-standards in its Gmail and other Google Apps products, on a browser-specific basis.

Interoperability Issues

However, this doesn’t come without a caveat. In an interview with Infoworld, W3C’s interaction domain leader, Philippe Le Hegaret, has warned against getting too excited about the current state of HTML5.

Le Hegaret believes that HTML5 is not ready for production yet, noting that the W3C still needs to make changes on APIs. According to Le Hegaret

"The problem we're facing right now is there is already a lot of excitement for HTML5, but it's a little too early to deploy it because we're running into interoperability issues, including differences between video on devices."

He adds that the problem lies with whether HTML5 can work across browsers. "[A]t the moment, that is not the case." Le Hegaret acknowledges that companies are already implementing portions of the HTML 5 spec in their various applications. However, these are mostly in cases where the environment can be controlled, such as browser-specific content. It’s a different story when it comes to the "open web" though.

Privacy Concerns Heating-up

Lately, a number of privacy concerns have surfaced in the HTML5 context. Recent commentary by Tanzina Vega, a New York Times technology reporter, shone light on the issue. Of particular concern was the complexity related to removing HTML5 persistent data (similar to existing HTML cookies) from your computer, after visiting a website that utilizes this mechanism for storing information about you, your preferences or your activities.