In reply to Graham:
> I've always been under the impression that yo-yoing referred to top roping a climb many times (up and down and up and down).
... then you've always been under the wrong impression!
Yo-yoing resulted from the tenet that pre-practising moves was not permitted, so after failing on any attempt a climber was expected to lower immediately to the ground and try again from there. The temptation to hang and check out the next holds or the next move was so great that this style was constantly open to abuse and never going to persist, but it still took quite a few years before what we now call headpointing would take over.