Join Date: Feb 2010
Location: Loudoun County, VA
That's a weird email to get... what was the email address it was from?
I'd say it's just junk mail. If it was actually facebook (or their "Ads Team") they would be able to remove whatever the offending application was themselves. They control the website, they can remove anything they don't want from it, and they don't need to ask you to do it.
I'm thinking it was a competing ad agency trying to get the other company's circulation number go down, or just someone with a bizarre agenda! Or it could have been someone trying to get you to click a link in the email that was in the email that was sent...
I think just ignore it; take no action.