If you target all countries you're going to need to make sure you have GEO redirects set in place to distribute the traffic. As dudeman said even if you're just targeting the US it's a good idea to include GEO redirects as there is a good bit of international traffic mixed in. Based on the country redirect you can then use scripts to redirect based on carrier.
Not sure what you mean by step 3 - can you explain?
The traffic isn't free it's just a helluva a lot cheaper.