Haven't tried it, but I'm sure it'll be effective. Eating every 3 hours is great advice because it helps to keep your blood sugar stable and prevents you from getting too hungry so you don't binge. Most people who skip meals end up pigging out at the end of the day. However this diet also limits you to about 1400 calories a day. Anyone who is overweight and eating 1400 calories a day will lose weight (especially if you incorporate activity). If you were eating fast food every 3 hours, you wouldn't see any success and would end up gaining weight I'm sure.
Many other diets are based on the principle of eating several small meals (Slim fast diet = 2 shakes, 3 snacks, and a sensible dinner which adds up to about 1200-1400 cal. a day, Body for Life = 3 smallish meals/3 snacks adding up to between 1300 - 1600 cal. generally depending on your starting weight, etc.)
I think the idea to really take a away from these diets is to eat smaller well balanced meals several times per day as opposed to skipping meals and then binging later.