Some users of the jutsu are Kakashi, Gai, Genma, Kabuto, etc. It can often be seen when Anbu members are dismissed.
5Can you expand your question a little bit? like add references to manga/anime(where you see it happen)– RobinJul 8, 2013 at 11:21
iKlsR has given the correct answer. Kakashi uses that technique during Chunnin exam Preliminary round and Gai uses it to appear infront of Rock Lee to punish him for using a forbidden move against Sasuke.– Ero SenninJul 8, 2013 at 15:13
The most common one I know of and I think you are talking about is the Body Flicker Technique (also known as Teleportation Jutsu, or Shunshin no Jutsu).
The Body Flicker Technique is a high-speed movement technique, allowing a ninja to move short to long distances at an almost untraceable speed.*
To an observer, it appears as if the user has teleported. A puff of smoke is occasionally used to disguise the user's movements. It is accomplished by using chakra to temporarily vitalise the body and move at extreme speeds. The amount of chakra required depends on the overall distance and elevation between the user and the intended destination.
It could also be a shadow clone.
3It seems very unlikely that it'd be a Shadow Clone. Do you have anything that could back up your opinion?– JNat ♦Jul 19, 2013 at 13:32
1Meh. There is no jutsu that make one appear/disappear. It's only shadow clones that disappear. I remember an episode where naruto had to master his wind nature energy, and talked with asuma sensei. It was a shadow clone who was talking with azuma, when they were done talking, naruto undid the shadow clone and azuma mentioned it was a shadow clone. it was episode 56, minute 7:35.– 131Jul 20, 2013 at 1:08