new - have question on posting

I just tried to post on the Chevy Malibu site and my thread has an envelope with a black seal on it. What does this mean? Did I do something wrong when doing the post?

The black dot just means it's a thread you've posted in, nothing more, you can use the black dots to track what you've posted in and what you haven't.

If you go to the forum index where you view the threads and scroll down, there is a key to the different envelope meanings.