The real reason that Wave has failed to gather the following of so many other great ideas is that they launched an experimental product that they hoped would go viral and become wildly successful, but they restricted it to the smallest group of people possible: those that don't use Internet Explorer. They probably thought that the "explosion" of popularity of Wave would help them grab browser market share (or at least take it away from IE), but they failed miserably at that as IE usage is actually up now. The claim was that they were focusing their efforts on the quality of the product or some crap like that, so they didn't want to waste time on IE compatibility, but not supporting the browser that had and still has the largest share of the market is just suicide. And let's face it, it's not like it's that hard to get an AJAX app to work in IE - I did it before it was cool and that app still purrs on IE, Firefox & Safari without me really trying to support them. So it seems to me that Google deliberately "broke" Wave on IE. Which means they did the opposite of what they were claiming to do: not wasting time on IE; instead they wasted time on making it not work and wated time on trying to get browser share. Lesson learned? I doubt it. And I'm pretty sure no one here will agree or learn from the lesson, but at least I've tried. The lesson, in case you didn't get it, is: don't launch a product that people might have a hard time seeing the need for to the most restricted segment of a population: those not running IE (you can apply this to other markets, too).