As a way to help consumers identify organic foods, this seal was created by the USDA. The use of this seal is voluntary not mandatory for use by the food product manufacturer, so you won't necessarily see the seal on all organic foods. There are, however, some guidelines for the usage of this seal, and it is important for you as a consumer to understand what the seal means.
First, before a product can be labeled organic, "a Government-approved certifier inspects the farm where the food is grown to make sure the farmer is following all the rules necessary to meet USDA organic standards. Companies that handle or process organic food before it gets to your local supermarket or restaurant must be certified, too."
This seal can only be used on products that are at least 95% or more organic. Anything below that, the food manufacturer cannot use the seal nor the words "Organic" or "100% Organic" unless it meets the USDA standards. So, when you see this seal, know that the product is at 95% or more organic made.
For products that contain at least 70% organic ingredients but under 95%, the manufacturer can put on the packaging the words, "Made with Organic Ingredients." Again, they cannot use the USDA Organic seal. Any products that contain less than 70% of organic ingredients can list organic ingredients in the ingredients list on the side, but the manufacturer cannot make any organic claims on the front of the packaging.
Here's more information on the Organic Food Standards and Labels.