Not sure the thinking behind the name. With the World Series just around the corner, one would think that a pop-fly is not a good thing (unless it was a sacrifice). Another possible name might have been ground-rule double (not quite out of the park--but it's still in Beta). Anyway, a pretty cool Silverlight mashup building application called Popfly was just released today. I spent 2:45 creating my first mashup that got pictures from Flickr and put them on a picture stack. You could then navigate...