Understanding the Oxford comma.

[arpad]

Oxford comma AKA Serial comma

Comments

[rukenau.livejournal.com]

Which is funny but quite untrue, though.

[arpad.livejournal.com]

elaborate?

[rukenau.livejournal.com]

The meaning doesn't change quite as abruptly depending on its presence or absence (cf. Russian, where its usage is wrong). It is purely a matter of style preference.