Help!A problem about using email.

In China ,when you have something to talk,dial him directly.Why you foreigners use email so much?Or ordinary people don't use ,just businessman ?I'm a new comer in  international trade,so i am puzzled about whether sending emails to the trade manager of other company really works.

More and more Chinese know italki,whether this place will be occupied by we Chinese I'm a little worried about it.It's not funny......

Talk about a litte funny thing happened in China but not about Chinese      Every time when i see  foreigners on the road, only if i have a look on them,they wouid say hello and give a smile to  me .it's friendly,but surely we don't know each other before.In china ,we hardly talk to strangers.unless it's a really beautiful gril here or borrow a fire.So why you  foreigners do this in China ?Certaily it's a good thing .i'm just curious about of it .