Google bought youtube for 1.65$ billion and is now paying 3 times as much for something which is basicly an email marketing list and who get all their customer

Google bought youtube for 1.65$ billion and is now paying 3 times as much for something which is basicly an email marketing list and who get all their customers from aggressivly marketing on adwords? They have an good idea but the price is pretty steep. On the other hand they have been good at buying up local companies doing the same (they bought mycitydeal which operated in scandinavia/germany)