Oxytocin is different from most hormones because its effects are due to positive feedback loops?

True.  When too much pressure is applied to the cervix during childbirth, oxytocin is released and stimulates uterine contractions, which causes more oxytocin to be produced, and so on until the child is delivered.  This is called the Ferguson reflex.

Positive feed back in this case is neuronal, not hormonal. Prolactin also acts similarly.

True. Most hormones are released to stimulate endocrine glands when the level of their particular hormone drops in the blood plasma. Oxytocin is released in several cases: it responds to dilation of the cervix during childbirth to stimulate uterine contractions; it also stimulates mammary glands to release milk in response to a suckling infant, which is called "milk let-down reflex". Oxytocin levels during pregnancy also increase maternal instincts to love and protect the fetus and new-born infant. All of these are positive feedback loops; wider cervix=more oxytocin; suckling infant=more oxytocin and more milk; pregnancy and delivery=more oxytocin to accentuate maternal feelings.
There is even evidence that oxytocin increases in response to physical nearness of lover, husband..in other words, it helps women 'get in the mood', but this is still being researched. This would definitely be a feedback loop, though!