I was reading the 85 post and someone said that because Jiraiya was surprised about itachi's flames that it must be some jutsu he learned on the way. Because he would recognize it if it was a uchia bloodline ability. I think (no I don't know) that perhaps there are jutsu's or even blooline techniques that other clans inside hidden village don't know about. Just because you are part of a village doesnt mean everyone in the village knows all youre clans abilities.
also is the shadow jutsu that shikimaru(not sure on spelling sorry) uses a bloodline tech or is it just a clan jutsu. if it is just a clan jutsu why don't others know how to do it (outside of thier clan). in other words why dont certain jutsu's cross over between clans?? I dont remember any mention of shikimaru's shadow teck being a blood line. if some one could clear this up for me i would appreciate it.