Is Marijuana really harmful for you?

I am really interested in this topic because I always wanted to know the truth about "weed" . Is it bad to use? How many people use it? How has it impacted America? and a lot more question that I want answers to. To begin with, we probably all know one person that smokes marijuana or used to, and I'm sure I'm not the only curious one either.

Basic facts about Marijuana

There are over 200 slang terms for marijuana. Marijuana is a drug-ish substance that causes change in the way your brain functions, for few hours. Marijuana is one of the most interesting plants on earth, it can have all variety of colors. It can be taken in many ways, it can even also be baked. Unleast one third of americans have used it once in their life.

http://alcoholism.about.com/od/pot/a/marijuana.htm

Marijuana, how bad is it?