I find it interesting that it basically has the same function as Kayak Explore: http://kayak.com/explore - but with a completely different presentation.

Not exactly, this shows daily price changes through a few months, You cant see this in Kayak's interface.

WOW I did not know about it, looks awesome! Thanks for sharing.

If you have specific airports in mind, you can click the chart icon on the flights search page to display a similar price graph.