In reply to Brendan:
here's one. It's a bad idea to use the dynamic belaying described in this article for trad climbing because it relies on standing away from the base of the cliff. Many gear placements will not hold with the outwards force this would place on them. Dynamic belaying can be useful for trad climbing, as it can reduce the load on poor runners, making them more likely to hold. It is best acheived with a well-timed upward jump as the leader falls (assuming the landing zone is safe for the belayer if the gear rips). If the gear rips the belayer will land on his arse on the ground. Try not to drop the leader in this case, as that rarely helps.