I don't know about the rest of Europe, but these have come out of Sweden (many have since relocated): Klarna, Rebtel, Mojang, King, Wrapp, Soundcloud, iZettle,

I don't know about the rest of Europe, but these have come out of Sweden (many have since relocated): Klarna, Rebtel, Mojang, King, Wrapp, Soundcloud, iZettle, Tictail, Spotify, Skype. Of course, depending on your definition for "big success". For a small country they sure are, and most countries in Europe are pretty small. I doubt we'll see a Google or Facebook come out of Europe, if just because of the lack of engineers willing to relocate to another country within the EU for such a job. There is no country in Europe which can hire 50,000 qualified people like Google, except for maybe Germany.