I am confused because you only put it in ONE tank and it works for 3k miles.
I have seen additives that you treat a tank with but you have to treat every tank. also, if it were spam (which it resembles) why doesn't it have the web site on it. I also wonder if this thread is spam as well.
Be the change you wish to see in the world
Another thing that is so funny about it is that this person drove exactly 459 miles and used exactly 11 gallons of gas. I don't think I have filled my tank in several years and the pump reading come out to an exact gallon. Some people will look at the gallons and never look at the numbers following it and then want to say they got this great gas mileage and it sounds like what this person did. If so and he actually used near 12 gallons that would drop his mileage to 38-39 which wouldn't be but 3mpg better than samasaurus says his wife's 2003 gets. Only using it every 3000 miles sounds more like an injector cleaner than anything I can think of.
Edit: After looking up their web site it seems to do everything that all fuel injector cleaners claim to do.
The only product I have used that works is Lube Control FP Plus.
It seems based on my gas logs that it gets me about 1 to 1.5 mpg.
The two bottom tanks I forgot to add the FP Plus
The high tank had about 40% of highway on it.
Usually I only have about 10% highway on each tank.
Once I graphed it out it proved to me that the gas additive did work.