hourglassy .com... has nothing to do with Mozilla. The page is also too blank to be from Mozilla as they normally have various mozilla.org links on top and or bottom of page. Perhaps it was a fake Ad that popped up on the site as the url leads to a page about a actress. Firefox updates are either internally in Firefox or by download from '''*.mozilla.org/''' like say www.mozilla.org/firefox/all/ I would not be surprised if this were to actually try and get you to install a extension (if you clicked on the green Update Firefox) that may start with name of FF as Mozilla blocked several of these extensions from similar fake Firefox update sites in last month. addons.mozilla.org/blocked/ btw the official abbreviation is '''Fx''' and not FF so that would be another sign that it was likely fake if it were to try and install and extensions with FF in name.