Why are there flashing ads on facebook? Virus?

[PJ]

Today on facebook I started seeing these annoying flashing spam advertisements. The kind that say congrats you won. I know this is not a normal facebook ad and im afraid i have a virus. facebook is the only website it happens on and it happens on chrome and ie. I scanned my entire pc with norton and it came up with nothing i also deleted all temp files cookies history, etc. Is this a virus?
The some adds say like find girls in your area, congrats won a free mack book, stuff like that. not normal facebook stuff

[abraXus]

no, it's not a virus, it's just annoying advertising

[Uzair]

I would def. check the url, there are people hackers mostly trying to create fake pages to trick people in to submiting their information.

Always type facebook.com and never click on the facebook.com link on any website. Because the internal link could be something else.

[gah!]

Chrome sucks... it is an over-hyped and over-rated system memory hog... and isn't as secure as many seem to think. Use a different browser.