I don't understand why Poland is not mentioned in this article. I know a lot of Polish engineers working on H1B in a valley, but I don't know how exactly this number compares to Romanian engineers. What's more, at Microsoft, Facebook, Google and Nvidia Polish interns were the largest group of interns on J1 visa last year (as far as I know J1 is required for all countries except USA and Canada). Also, a lot of arguments stated in this article also hold for Poland.