Will HTML be replaced by any new technology?

No, they won't.

All new technologies promise to be The Next Everything That Solves All Your Life's Problems And Brews Your Coffee, but few do (I haven't found anything that would do both simultaneously :/ ).

Silverlight and Flash suffer from the Magic Window syndrome - they're just a box of multimedia inside your browser that's separated from everything else. Sure, they can call JavaScript to the outside world, but that's when they become addicted to JavaScript and (X)HTML. "Yahoo's new framework" use JavaScript, CSS and HTML, so that's out the window already.

What we will se (and do see already) are various frameworks and toolkits and stuff that help you with various tedious tasks. But, if they work in the browser, they all will use (X)HTML, CSS and JavaScript at some point of their stack.

I'm from the future, and no, it's still here.

i don't think they'll replace .HTML just like I don't think anything has replaced .TXT. I am fairly sure these new technologies will, over time, enjoy wider adoption and use. And probably someone will come up with a major break-thru and we'll all flock to use that new cool app-building client-delivery tech.

But I would wager whatever that new thing is it still comes to the browser embedded in an html page

HTML won't be replaced as a standard any time soon. It's too wide spread a technology, and the amount of re-education required among people working with webapps and websites to switch technology completely would be massive and very costly.

HTML will however, like any other technology, evolve. Look at HTML today compared to 10 years ago, it's the same language in the basics but the way we use it, and add-on technologies have changed it quite a lot. Even a high tech, premium site made 10 years ago will look feeble with todays standards.

So, while HTML will like stay "the same" (i.e. follow the natural evolution of a standard), the technology behind the site (php, .NET, JAVA etc.) will probably be more likely to change.