The stars could mean nothing, something, or a combination of things. The origin was Pagan, with the five points being assigned the meaning of the five essentials for life, Earth, Fire, Water, Air and Spirit. The Church adopted it, declared all things Pagan as evil, and reassigned the points as being the head, outstretched arms and legs of man. Over the aeons it evolved to mean many other things, as well, including the Star of Bethlehem, Don't Mess with Texas, a deep need to connect to the cosmos and'or something larger than ourselves (how many national flags around the world feature star or other symbols of the cosmos?), tacky (in the eye of the beholder) decoration, or a celebration of this or that holiday.
It could also be, and in some cases it absolutely is, an updated version of its displayed meaning during WW II:
Brown star = Veteran of the military
Blue star = Family member currently serving in a War
Red star = Family member wounded in combat
Gold star = Lost a Family member in a War
But on most houses, it's just decoration. Nothing more.