This is an interesting video on the history, use and repression of Cannabis.
It is good to get informed. One problem with Cannabis is that Marijuana was unfortunately indelibly linked to the hippy counter cultural movement, and became a political football between the left and the traditional order. The merits and detriments of Cannabis have for too long been lost as a casualty of the culture wars. Trying to have a rational discussion until recently has been difficult, but now I think that society is waking up and beginning to take a second look.
It remains odd that the Federal government continues its inflexible opposition to Cannabis. The Obama administration continues the Bush administration´s policy of opposing states´ decisions to allow Cannabis.