The Oxford comma is loosing popularity because of laziness. On an iPhone the comma is on another keyboard and you have to click at least once to type a comma and even I find myself at times not doing it. Like right now. Also in the 140 character twitter world it is one precious character.
Most of the time I use Oxfords. Not every third word but enough to properly present what I want under stood with out confusion such as the "Let's eat grandma. Without the comma this could be a kindly notification OR a stomach turning event.
Of it can take the place of a verbal Rorschach test. Depending on your opinion cute fluffy black and white animal. The panda eats Shoots and Leaves. Which, by the way, is a very good grammatical commentary and very entertaining.
DM
PS: I am strongly in the Oxford comma school