It's a cool in a geeky sense that destinations drop off the map when I click back and forth. How does this solve my problem as a customer though? I know I need to get from A to B. How does the map help me choose which flight from which carrier on what day?

If you leave the destination open and limit by price, you can answer questions like "Where can I go for $500"?

This is all I've wanted from a flight search product since forever. It will be awesome when it's more international!

http://kayak.com/buzz has had this forever.

Try http://www.kayak.com/explore/ which gives the same max budget parameter but on a map from an origin city.

True. The UI however is something else. Really gets out of the way and gives you what you are looking for. Feels effortless to use compared to the usual suspects in this domain, IMHO.

It's helpful in places like San Francisco or New York, where you have options about which airport you can use.

For example, I looked at a ticket from SEA -> SFO. When I zoomed in on SFO, I can easily see how much it is to San Jose or Oakland as well.

It's also just fun to enter your departure airport and see "where can I fly and for how much?"

The map is misleading when showing result for flights with stops. It should show/highlight intermediary cities in this case