actually products can have different information just because they are sold in a different state. and that's without taking into account that sparkpeople live all over the world.
manufacturers will use different recipes for the same product [plain oreos seem to have a vegan version and a nonvegan version out there at the same time] because of availability and price. which in turn can lead to slightly different nutrition info. plus there isn't really an effective way to purge old entries, so that if the manufacturer reformulates the recipe with different nutrition info, both will stay in there.
and don't go by the internet, go by the container in front of you. that's the best guide to what you're actually getting. for things that don't have containers [apples, cabbage, etc], spark uses usda info, which is as accurate as you're going to get without testing half of what you eat.
-google first. ask questions later.