Given that the sale of marijuana for medicinal use is legal in nearly one out of three U.S. states, and California and Colorado are considering total legalization (with taxation), pot's cultural tide is rising.

So is its business side. California's biggest dispensaries are starting franchise operations and establishing branding. There's an emerging industry trade show and a lobbying, marketing, and consulting firm strictly for cannabis in Oakland, California.

Harvard economist Jeffrey Miron, in a February 2010 paper, estimated the market to be $14 billion. Others have pegged the medicinal retail market at $10 billion to $40 billion, based on usage, demand, and pricing data. 

By the numbers:

Estimated worth of the medicinal marijuana retail market: $10 billion to $40 billion

Number of U.S. states in which medical marijuana is legal: 14

Year the industry effectively began, when California passed legislation legalizing medicinal marijuana: 1996