Not so fast. For better or worse, often people won't assume things are going to be done on time, or in the way that you said. They probably don't blame you for it, but they're going to try not to assume completion erroneously, so they'll err on the side of assuming you haven't finished on time or completely. So when you're done, tell someone.
Don't forget to send the yay mail.
When you've finished an effort of any large-ish size (e.g., a release), tell people about it. Maybe it's an email confirming you've done X, Y and Z on some date. Maybe it's an updated wiki page or a status in a project management system. It doesn't matter how you do it; just find a way to confirm for people that you're really done. That explicit closing out of a project keeps everyone on the same page, and then you can go on to the next thing. Celebrate just a little, then move on.
You deserve your yay.