Pop up?
#2
Are you being asked to install Flash, the software that helps to display animation on almost every site around? That's the only popup I can think of, and it is actually coming from your browser, not the F150online.com site. (the browser is trying to display a Flash animation and does not have the "plug-in" to render it, so it is asking if you want to install it)
#5
It may be that some of the new Flash ads that have been running from Google require a newer version of Flash that you currently have installed. Have you read the full message on the popup? It's possible that the ad(s) that need Flash are only running on this site right now. (or not running on the other sites you visit) Without the full text of the message you are receiving, this is only speculation. I suspect the popup tells you what you need to know.