Canvas element question

[1089]

Hi,

I am to design a new webpage for a company in HTML5 and they want effects I usually associate with Flash.

If you look at http://www.beautyoftheweb.com/#/experience/ you will see the nice boxes that pop up when you hover over them and float to the middle. I know this is done with the Canvas element, and some JavaScript, but I have no idea how this is accomplished. Could someone point me in the right direction? (I also saw AJAX in the source code)
I've looked at the HTML5 info on w3cschools, but the canvas element is discussed in a very basic manner - gives me no insight into how a page like the one I mentioned above would function.

I'm thinking of a mindmap styled intro page, where the users are presented with the company logo in the middle and various boxes surrounding it. Clicking on one of the boxes loads it to the center of the page.
How would this function with search engines? Links? I know that AJAX presents difficulties when linking to a page where you want to display spesific content that was loaded dynamically.

Futhermore, what would be a good way to show users with older browsers not supporting HTML5 the same info in a relatively similair fashion?

Thanks!!!