It's amazing what fundamental technical innovations can lay around waiting to flower at the right time. Like seeds in Death Valley sprouting after a rainstorm, the sturdy little XMLHttpRequest object in Web browsers is taking the world by storm. Here's a page from Fiftyfoureleven.com with a large list of links of people and projects based on XMLHttpRequest -
XMLHttpRequest & Ajax Based Applications.
This is great stuff. I wonder what it was that finally made this explode onto the Web developer scene. It's been around at least five years in InternetExplorer - but I suppose it was languishing until the rest of the community got around to implementing it. I'd love to see a timeline of it's deployment in other browsers and it's adoption.
(later) Ah, I see now the connection between Ajax and KnowNow.