Since the sibling comments already explained the Finland-Swedes, I'll just add a bit of trivia relevant to this crowd: Linus Torvalds is one of them. His first language was Swedish, and apparently he's never spoken Finnish particularly well.
[0] http://www.linuxveda.com/2011/11/02/which-is-linus-torvalds-...
But then there are Finnish rock stars who lived a year in Stockholm and then pretended they've forgotten all about Finnish language. (Andy McCoy of Hanoi Rocks, I mean).