Thanks, Sinweiy for that informative post.
Maggot, yes, "lama" is a Tibetan word, a term for a (dharma) Teacher.
Tibetan Buddhism has a very special tradition different from the other forms of Buddhism, which is that the Lama/Rinpoche would give indications, prophecy, on where to find the next incarnation to take over his job after he dies. In addition, there are other lamas/yogis who would have visions of the new incarnation. After that they would go on a search, find the person, and do a test and if the person answers the tests perfectly, and, after consulting the Spiritual Oracle (not the Matrix one

) he can be considered the right incarnation.
I am personally not from Tibetan Buddhism, but one of the moderators, Origami, is. Perhaps he can share more insight on Tibetan things, if you have any questions.
In Buddhism there are three major traditions of Buddhism, but ultimately the teachings lead to the same goal. The three traditions are Theravada, Mahayana, Vajrayana. In additions there are different sects which focus on different practices, dharma doors. In Buddhism there are 84000 dharma doors, which explains why there are different practises. Each dharma door is like a medicine, if it works for you, then it is the best medicine.