HTML 5 is all over the place. I started hearing about it first when i was reading about the canvas tag about an year ago. But all the noises reached their pinnacle when the iPad was launched with HTML5 support instead of Flash.

ExtJS.com has put together a nice article explaining HMTL5 in brief (Click here for the article) while diveintohtml5.org gives a detailed explanation on the features.

As the article puts it, HTML5 is just a part of the family of  specifications that people end up calling as HTML5.

Some of the highlights of the HTML family are as follows:

• LocalStorage,  a client-side key-value database, meaning it is stored in the users browser (similar to cookies but it’s designed for larger quantities of information)
  
• Graphics support with the <canvas> tag (it is a JavaScript controlled drawing area)
• Video and Audio support with the <video> and <audio> tags
• New structural elements like <nav>, <header> , <footer>,<aside>, <article>, <section> tags

• New inline elements to mark things like time and numbers (<mark>, <time>, <meter>,<progress> tags)
  
• Web Workers – enables JavaScript to work on the background and allows spawning of multiple threads
• Offline Web Application – support to run web applications offline
• Geolocation – api to  support getting location information using IP address, wireless connection, etc
• CSS3