Not quite. There are 2360 individual tasks. Each one would take no more than 15 seconds, perhaps a bit more. Spread those across the several hundred people that are on MTurk at any given time, and you can get done in 2 minutes.
The 4 multiplier comes because as you said, each individual task is fairly unreliable for quality. He's testing each individual domain name across 4 people (not the same 4 people each time).
The 4 multiplier comes because as you said, each individual task is fairly unreliable for quality. He's testing each individual domain name across 4 people (not the same 4 people each time).