Kayak explore tool is great. There have been numerous startups trying to build the same, but to make it useful one needs to have a lot of data. Kayak has arguably more data than any other metasearch engine.

Map is definitely useful and for an opportunistic traveller is a great tool. Flystein is not trying to compete with it. Where it is good though is a constrained trip, with fixed dates and requirements, or a complex trip. Map like this would not show a multi city trip.

The problem with Explorer is that it is showing lowest prices which somebody found some hours or even days ago, and most of these cached prices are gone when you are trying to validate them but sometimes you could get lucky ;)

It is like a multiplied problem of metasearch stale/cached prices, also some OTAs seems to show stale prices on purpose to play the bait and switch game...

Yeah, I've noticed the caching problem a few times, though all of the prices I listed were actual prices I sent friends who purchased or I validated by following the process to the actual fare page. Though sometimes the really cheap fares are with budget airlines who upsell for carry-on and checked baggage lifting the price.

There were a few too good to be true Air Canada prices (sub $400 to India) I saw a few weeks ago, but those didn't exist once checked.

I've been able to convince friends to purchase tickets who would otherwise not have traveled by posting the fare to Facebook. Chicago seems to be a popular one my friends want to go, and they end up being convinced when they see a sub $100 RT ticket from California.