A University of Oxford Style Guide has decided to go minimalist on all the grammarians and drop the oxford comma. They’re making big decisions over there. Watch out:
‘“As a general rule, do not use the serial/Oxford comma: so write ‘a, b and c’ not ‘a, b, and c’. But when a comma would assist in the meaning of the sentence or helps to resolve ambiguity, it can be used – especially where one of the items in the list is already joined by ‘and’ [for example]: They had a choice between croissants, bacon and eggs, and muesli.”’
(via MoJo)