http://www.udayton.edu/mary/mar.htm
Marian Symbols in the Buffy the Vampire Slayer television series on the WB
-Michael P. Duricy, MA, STLIn 2000, I completed a dissertation on The Virgin Mary in Film. One of the areas studied was the brief but explicit use of Marian symbols in a great many films, most of which had very limited religious content. From the frequency of examples over time and across national boundaries, I concluded that certain implications have become conventional for using these episodic Marian signifiers: indicator of death or possible death; comparative standard for measuring the virtue or vice of a character; opponent of the demons; analogue of the female romantic lead; dea ex machina; and Catholic or ethnic artifact. There is one final convention involving the Marian symbol. Brief, but explicit, Marian content is sometimes used to identify a symbolic Marian character.
I, personally, did not start watching BtVS until itís fifth season on the WB, savoring the pleroma of the Buffyverse only through reruns. Hence, I had absorbed the above hermeneutic from my general research before engaging myself with Buffy Studies. Though casual observers may not have noticed [due to the brevity of their appearance], Marian symbols were overtly shown rather frequently in BtVS. In my opinion, the purpose for using this episodic content corresponds to the above conventions, already long established by a history of use in the media of social communication.