do people in Iran use American email providers?

not sure if this is true or not, but I heard a rumor of Uday Hussain using a Yahoo mail account with a trivial to crack password. Which gets me thinking - do people in countries that can be either spied on by the West or even get in a war with us use their own local email account providers? Would a war with Iran lead to lots of people there losing access to their gmail accounts?

I have an Iranian correspondent who has a gmail account.

This link notes:

I don’t know what would happen to Iranian access to US email providers in the not-very-likely event of an actual war.