Copyright date doesn’t mean a lot any more, as copyright belongs to the creator for 70 years after that creator’s death. When shown with the circled c symbol, a date may mean when copyright was registered by filing copies with the Library of Congress. But indeed, if the Web site shows it was updated later than that, there’s at least some information there that’s newer.
I agree with Masha that the important date for a Web citation is when you collected the info. It’s a new world out there.