What can Weeping Angels teach us?

Since their first appearance on the "Blink" episode of Doctor Who, the alien species known as the Weeping Angels have garnered a large popularity amongst the fanbase that rivals that of series mainstays like the Daleks and the Cyber Men. Instead of asking why the Weeping Angels have managed to acquire such popularity, this topic asks the writer to investigate the symbolism encoded into Weeping Angels. How can a viewer interpret these creatures? What can these interpretations reveal about the viewer's reality? In a sense the topic centers around two key concepts. What are at least some of the possible interpretations and how do these interpretations comment upon the viewers' reality?