The Uchicha Clan is most known for their bloodline limit, Sharingan Eye. I havent seen the episode (waiting for A/A) but I do know that you can advance that bloodline limit, like when Itachi used his Magekyou (however u spell that) Sharingan Eye against Kakashi and attacked his mind. So that means that all bloodlines can be advanced so not everyone in the village may know about the advanced limit.

Shikamaru never said his technique was a bloodline limit. But not everyone knows how to do it because they obviously never learned how to use it because everyone else has their own strong jutsu's.