Link to the mobile apps here
Web version here
Profile - the site and app both allow you to enter your height/weight/daily activity level and weight loss goal. From there you are assigned a base calorie intake goal. Mine is 1370, which sucks ass and I dispute it every day. This has to do with the BMR (Base Metabolic Rate) which is the minimum amount of calories you need to perform basic functions like breathing.
Tracking - to keep your daily calorie intake tracked, use the "My Diary" or "Food" tab. This is where you enter your meals, snacks and water intake. The search options to look up food are mostly accurate. There are entries already loaded for restaurants, brand name foods and generic foods. Adding new foods to the database is easy too. There is also an option to create a record of nutrition information for your recipes, meals and favorite foods. I created entries for the coffee I drink every day, the egg white veggie taco from the cafeteria and my Sunday Football Chili.
Exercise - Remember that base calorie level? That does not count activity over the usual sitting at your desk all day. You can add your workouts and it deducts the calories burned from your daily intake. Today I ran 40 minutes at a 9:28/mile pace. With the tool I added in that I ran my 40 minutes, but it doesn't have an option for 9:30, so I picked the 10:00/mile pace. MyFitnessPal says I burned 419 calories, so I can eat an additional 419 calories and that is added to my daily goal/limit. I think this is pretty accurate too. Using my GPS watch I get about the same numbers. When I do Ripped in 30, I count it as "Circuit Training", 35 minutes is 293 calories. It feels like 500, but I know 293 is realistic. At the very least it is more accurate than the calorie counters at the gym.
Progress - I can track my weight, weekly goals and there is an option for adding a progress bar to your own blog
Motivation - after finishing my tracking for the day, it tells me what I would weigh if "every day were like today..." This can be motivating or really defeating. There are also charting options so that you can see how you compare to your weekly goal - which is nice. This way when I eat a bunch of shit one day I can cut back a little the rest of the week and not feel too terrible.
Summary - I really like this app, a B+. Its FREE too! I don't use it every single day, but I go through periods of a week every month where I use it daily. It keeps me honest about what I'm eating and when I feel bummed about my 5 vanity pounds I can SEE that I am not eating to lose weight most of the time.
Update: new iPhone version has a bar code scanner option. I just scanned the bar code on my diet soda and it added the info to my daily total. Sweet!