a) It needs an 'OR' operator. If I enter from as 'Western Europe', I'm told it's too broad, which is ok - but I'd like to be able to choose a few convenient starting places rather than do a separate search for each. (To those who say a random starting location is a bad idea: actually, in Europe, it's a pretty good one. Depending on my destination, I've found it useful to travel up to 8 hours by train to catch a decent flight, and I'd consider taking a low-cost flight pretty much anywhere in the continent for a particularly fun-looking and decently-priced flight to far enough away...)

b) It needs better data. http://www.ltur.com/de/flug.htm?omnin=TopNavi-FL currently would let me get from Brussels to Punta Cana (Dominican Republic) for 411 Euros if I left tomorrow. Adioso starts at 490, and the second cheapest is already over 1000.

It's nifty; if it gets better data and a bit more flexibility, I could see using it. I travel a lot and have a pretty flexible schedule. For now, I'll be sticking with edreams, easyjet, etc.