Why do I see ads everywhere?

[Gamer]

It just started like 30 minutes ago. I'm starting to see ads under some status updates on my Facebook newsfeed, ads under the comments under a youtube video & on top of a youtube video (I know ads are usually on the popular videos, but I'm seeing them on all of them). I'm just wondering because I've never seen ads under people's facebook status's before. Is this a virus or something??

Thanks!!
I'm using Mozilla Firefox. I checked Internet Explorer & it happens on there too. It's weird because there's so many on Youtube, one on top of the video, one right under the video, one under the comments, & one all the way at the bottom. I've never seen it like this before.