Iaido is a style of sword techniques unique to Samurai bios, also accessible through the secondary kenjutsu specialty which allows for normal ninja to use it. Iaido revolves around the rapid drawing of the sword to perform quick attacks, and then resheathing the weapon. It was invented by the samurai because of their inability to use Ninjutsu, and the growing need to be able to combat ninja, who could use it. On that note, Iaido is quick enough to interrupt seal sequences, and some techniques allow for short bursts of high speed movement across small distances.
That's about the extent of my knowledge.