One of the latest tech buzzwords that has been given prominence by the success of the iPhone and iPad is HTML5. Apple has pitched this up-and-coming iteration of the web’s main building block as everything from an alternative App Store platform to the Flash-less future of internet multimedia. But what exactly is HTML5, and what are its benefits for you?

HTML (Hypertext Markup Language) is the fundamental blueprint of the web. When you visit a site, you see specific content – such as text, photos, and videos – because your browser downloaded a big chunk of HTML code that tells the browser where to access that media and how to lay it out on a virtual page.

Designers can build websites by using everything from powerful applications like Adobe Dreamweaver and Panic’s Coda to plain old TextEdit. In the end, the blueprint is still a set of HTML text instructions for placing this picture over here and that chunk of text over there. HTML is an open standard, which means that no single party controls it. And browser makers – like Apple, Microsoft, Mozilla, Opera, and Google – can support its layout and content-display features as thoroughly, or not, as they choose.

Upgrade from HTML4
HTML5 is not new – it began life in 2004 as a seedling specification called Web Applications 1.0, from the Web Hypertext Application Technology Working Group (WHATWG), a loose affiliation of browser makers and others interested in browser technology. Since then, the World Wide Web Consortium (W3C) – the primary web standards organisation – has helped to flesh out new specifications.

HTML5 is not ushering in a new era of the web by itself. Many of the new features and fundamental changes are powered by accompanying technologies, such as CSS3 (the latest version of Cascading Style Sheets, the technology that lets web designers control page layout and style) and JavaScript (the technology behind special effects and interactivity). So to keep this discussion simple, let’s use HTML5 as an umbrella for these symbiotic technologies.

HTML5 covers a lot of features; Gmail’s ability to store email offline, geolocations that determine where you are, and the ability to drag and drop windows and widgets in your browser, are all part of HTML5. Also included are ways for web pages to incorporate functionality, such as screen readers for the visually impaired, document editing via Zoho Docs (docs.zoho.com) or Google Docs (docs.google.com), and the uploading of files from you desktop by dragging them onto a web page.

By standardising the implementation of these features, browser makers find it easier to build them into their applications. That means you can enjoy a more uniform, intuitive web experience no matter which browser you use.

The fuss over Flash
One of HTML5’s critical innovations – and a lightning rod for the uproar between Apple and Adobe – is support for a new tag, called video, in the markup language. This video tag makes it easier for web designers to embed video without needing Adobe’s Flash plug-in.

Flash technology – used for complex animations, interactive banner ads, video, and games – is created with Adobe’s Flash software. You experience Flash content in your browser via a plug-in. But Apple isn’t keen on Flash.

In recent years, Apple has denounced Flash as a poorly performing, insecure, crash-prone battery vampire whose days are numbered. Not surprisingly, the iPhone and iPad don’t use it.

Apple has mobilised publishers to create HTML5-friendly versions of their sites and services for its iPhone and iPad. The business incentive to protect its App Store ecosystem is strong. After all, Flash creates rich web applications that could threaten App Store sales if developers marketed their apps independently. And at present, Apple gets 30 per cent of every paid app, game and magazine from its store.

However, HTML5’s sovereignty over Flash isn’t a foregone conclusion. It faces significant obstacles, the most fundamental of which is that it’s not yet finished, and may not be for another year, or three, or 10. When a platform as important as the web’s native language is in flux, it’s hard to get software makers and content producers to overhaul their code.

Moreover, Adobe has scored some Flash points with the most recent version designed to boost performance. It also supports smartphones running Google’s Android mobile OS.

Consensus building
Because HTML5 is controlled by a large and amorphous standards body whose members have varying priorities, lack of consensus on key issues has delayed finalisation of even small parts of the overall spec. Among the most important of these issues is which video format(s) should be supported by default in HTML5’s new video tag.

Apple has successfully pushed its H.264 format across the web. iTunes Store video is distributed in (DRM-encumbered) H.264, and companies like YouTube, ABC, and CNN have adopted it for their HTML5 initiatives. But portions of the technology are covered by patents, which, in theory, could someday be used to enforce hefty licensing fees.

Then there’s Ogg, which is favoured by the open-source community, but again there are concerns about possible patent issues. Google even introduced a new video format, dubbed WebM, and made its technology open source in an effort to settle the matter. But none of the key players can agree, so their sites are stuck supporting different video formats for non-Flash, HTML5 video.

What’s it to you?
It’s too early to tell whether HTML5 will usurp Flash or if the technologies will eventually coexist, perhaps carving out niches where they excel. After all, Flash lets designers create immersive, complex, animated online experiences that they can’t by using HTML5.

But things can move pretty quickly. Adobe could demonstrate a commitment to improving performance. Conversely, the W3C could finish the HTML5 spec early with an agreement on an official, non-Adobe video format or two that tips the industry’s scales in its favour.

In the bigger picture, HTML5 could usher in an era of unprecedented accessibility for text, video, and other web media. Never before have we had so many different connected devices and so much potential for sharing content across geographical, lingual, and visual boundaries. And in the web’s short history, the key browser makers have never been so close to cementing the web’s markup language.

Whatever happens as HTML5 matures, we users are the ones who win.