Most of the focus in the comments is on what makes a viable business model (ad-supported vs. pay-for-use) or a rational valuation (is Slide really worth half a billion?), but my reading made me think that O'Reilly was trying to get people focus on something bigger, specifically, is what you're working on worthwhile?
Like, if you got hit by a bus tomorrow, will you consider your life well-spent to have built that sheep thrower when you could have been doing something else?
