WW is a weightloss program, it's not like curves at all. They offer two plans.
FLEX asigns points values to foods. Points are based on calories, fat and fiber. The lower the calories, the lower the fat the lower the points. Higher fiber foods have lower points. You recieve a points allowence for the day based on your weight. Everyone also receives 35 weekly points to be used throughout the week. Essentially it is calorie counting. You can eat anything you want as long as you stay within your points allowence. Most people find though that they get more fo rthier points by eating lower points foods which tend to be veggies, lean protein, fruits ect. Though, you can have a Ho-Ho if you want to use the points for it.
CORE is the second plan. With core you eat from a list of core apporved foods. You don't count points, you as much as you want as long as it's on the list, but the catch is you have to only eat you feel satisfied, not full or stuffed. With core you have the 35 points each week to use on non core foods.
You can also earn activity points by exercising.
WW is traditionally offered through meetings where you weigh in, learn new ways of healthy weightloss and get support. The meetings are run by a WW leader. WW is now offered online in all areas as well or through an "at home" package available in some areas.
It's a great program and I really enjoy it. I do the Flex plan and attend the meetings. WW teaches portion control, healthy habits like drinking water and getting in those healthy oils (like olive oil). They encourage exercise, and teach strategies for dealing with emotional eating, dining out, holidays ect with thier "tools for living".
It's hard to sum it all up so I hope this helps a bit