Advertisment in my post?

Looking at responses to a thread I started, I noticed an ad piggybacking my post. When I logged in to remove it, it was gone. I know how some forums can be about spamming. This ad was there not of my doing. Is this normal or has someone hacked my account? What do I need to do? Thank You

There are certain ads that only show up when you aren't logged in. This is totally normal and nothing to worry about.