Additional rough estimation:
NYC has roughly 14 million people living in it...
If 5/7 or about 72% of NYC population (10 million people) make a 10 minute phone call a year at .04/minute, that would be an additional $4 million. WOW!!
Just roughly 3/4 of NYC population using the service for only 10 minutes per year can generate $4 million in revenue just on the .04 extra...
Now think national and even global and think how much money this company can generate just on the .04 alone....
Then you have to include $500/m branded keywords, $10,000/m national keywords, and local keyword registrations paid per month...
The sky is the limit!