Okay your answer annoyed me because I don’t see how the size of european countries really relates, whatsapp was popular because of group text functionality and messages being free I don’t think it had anything to do with international communication, that said whatsapp and viber took off during the recession when emigration was rampant so there could be something there.

Anyway, I went to investigate and the average US state is larger than the average EU country by quite the margin 190,000 sqkm to 126,000 sqkm.