So after someone new begins bjj, they inevitably ask the question "when are we going to work on takedowns?"
The curriculum varies from school to school, but really to answer the question, it is not emphasized much in bjj (much like groundwork in judo).
The heart and soul of bjj is grappling on the ground, learning the intricacies of all the positions. Even the rules of most bjj tournaments do NOT penalize you for simply pulling guard and forgetting about takedowns.
My opinion on the matter is this:
It is already hard enough to get good on the ground, so when you go to bjj... focus on ground work only.
Assuming that is all you have done, in tournaments, be smart and PULL GUARD to utilized your strongest moves a.s.a.p.
When you get to the point where you feel like you need to add takedowns, understand that it will take an even greater investment in time and seek out the best wrestling or judo instructors to learn how to do it right.
now a video of some of the craziest wrestling ever