Well, Live rock is placed and then taken (or sometimes just taken) From an actual living reef in the ocean, where all the 'stuff' lives naturally, once taken out of the ocean, the rocks still have all the living things on it, and its then put into our tanks, to make an artificial ocean in a box!
Thanks for the help but I been reading about fragging and I'm under the impression that the cool stuff is bought small and placed or glued onto the live rock to grow . Ive had a 10 pound piece for about a month and don't see to much happening,scratchn my head here.
Depends on what you are talking about when you say "cool stuff" or "neat stuff". Live rock, when pulled from the ocean is home to all manner of creatures that live in the various nooks, crannies, and holes in the rock. Starfish, tube worms, and so forth. Many of these survive the rock being harvested and eventually make their way to your tank in/on the rock you buy...as a result you will often hear the term "hitchiker" to describe them. It can be weeks or even months before you discover all of the hitchikers your rock brought with you. But there is no guarantee of what hitchikers survived the trip on your particular piece of rock. It's kind of like the lottery...sometimes you get luckier than others.
When you talk about fragging and gluing to the rock, you are most likely talking about corals. Corals can make it to you as a hitchiker, but it is not as common as corals do not often survive extened "out of water" periods during harvesting and transport of the rock from ocean to store to you. But hobbyists will certainly obtain small frags off of larger coral specimans, either from stores or from friends, which they then place on their live rock, sometimes gluing it in place...though that is not always necessary as some types of coral will self-adhere to the rock in fairly short order.