Anyone who has run into outdated, incompatible or buggy plug-ins trying to play audio or video on the web can see the desirability of this functionality. The web has been a multimedia experience for some time, and yet only now is there a realistic effort to create a universal and (hopefully) open way to present multimedia.
While HTML5 has be lauded as “The Death of Flash” (or Silverlight, or Java, or etc) I rather doubt that you’ll see a cleansing wave scour the internet the moment HTML5 is standardized. More realistically, you’ll a slow reduction in the use of proprietary presentation technologies as support increases as the user base updates their browsers and developers realize and embrace the advantages of HTML5. You’ll also see the spurious uses of Flash, Silverlight, etc taper off. However, many companies and developers have ENORMOUS resources invested in these technologies and probably won’t be giving those up completely any time soon.
#2 Continuing to Partition Content from Presentation
Hand in hand with CSS3, HTML5 will continue to push the design and organizational separation of the CONTENT of a site from it’s PRESENTATION (or layout). Right now there are still many HTML/CSS2 practices that have one foot in both of these camps, out of necessity or convenience.
This “content portability” is even more valuable with the means of consumption (smart phones, browsing devices, internet connected appliances, etc) continue to fracture the user environment and as content creators explore more and more ways to deliver a “single point of content” to a variety of markets.
#3 A Fist Full of APIs
Anyone who has created anything more complicated than a static HTML page knows that you very quickly have to start bringing in a universe of additional techniques and technologies. These are often so integral to basic website functions that you start to see the wisdom, if not necessity, of standardizing and bringing many of those functions into the HTML standard. Enter HTML5 APIs.
This arena is still subject to a lot of change (and what isn’t in HTML 5?) but a few strong contenders include: Offline Storage, Drag-and-Drop, Navigation, Document Editing and Media Capture.
Should you start coding HTML5 today? Despite the occasional humorous job listing requiring “HTML5 Experience” it’s very unlikely designers or audience are going to get very much value from deploying HTML5 tomorrow. There is still quite a bit up in the air. A quick look at Amazon will show that most of the respected publishers still have their HTML5 guides and tutorials as “pre-order”. That’s for a very good reason.
It IS a very good time to start dabbling with the possibilities and get involved with the growing community. Personally, that’s where I am. Experimenting with new tags, embracing the changes and just seeing what is possible.