Our service utilizes an advanced Geolocation service that checks all visitor's IP addresses and where they are located. If they are users in the United States, and only if, then they are directed to your video to watch it. This way, we're able to target directly to United States visitors with a high degree of accuracy.
While IP geolocation is very accurate, it isn't perfect. If a visitor is using a USA proxy but is actually outside of the country, there's a chance that they will end up seeing your video. YouTube will most likely still log this as a USA visitor, even though that visitor is not from the US. Other than that, our service has a 95% or greater accuracy that your views will be from the USA.
The view duration is anywhere between a few minutes and 5-6 minutes, though this varies. Shorter videos will have better view duration than very long videos. If view duration is exceedingly important to you, you might be interested in our YouTube High Duration Views service.