For anyone who thinks the Cannabis industry is very small and wont grow into much, have a look at this article. Corona (brewing) is investing $5.5 billion into Canopy Growth, one of the bigger Canadian MJ companies.
Not sure if the link will work if you're not a subscriber, there will be other articles, the last sentence pasted below.
Canopy would use the capital to build or acquire assets around the world, he said. About 30 countries are considering legalising medical marijuana.