There's a great, quite extensive article in the New Yorker about Washington's journey toward creating a legal marijuana economy. 

With the sale of recreational marijuana is illegal on the Federal level, the process of making it legal for sale in Washington and Colorado has proven fraught with peril -- and opportunity. 

Some of the issues are ones that face any entrepreneur in an emerging market, while others are unique to a brand-new experiment in legalization, yet all of them have lessons for entrepreneurs.

Some of the challenges and opportunities in building a legal marijuana economy: 

Market Dynamics

In Washington, the sale of recreational marijuana will involve policy, legal regulation, burgeoning new businesses and the cultivation of more than just pot plants. A market has to be created for legal marijuana. In the New Yorker article, questions loom. Will the black market survive? Will the legal pot be priced at a level that people will want to buy it? Will the market be interested in purity and "micro-brew"-style strains of marijuana? 

The hero of the New Yorker articles is, in some ways, a policy guru named Mark Kleiman, a professor of public policy at U.C.L.A. He was hired by the State of Washington to do, among other things, a market analysis of the marijuana economy in the state, as well as studying the demographic characteristics of the market. 

Retail Setup

The New Yorker article details the shifting dynamics brought about by the Washington ballot initiative that became known as I-502 on the retail level.

It used to be that marijuana was sold in the state only through licensed medical dispensaries. Now these dispensaries are about to be supplanted by so-called "I-502 stores." In these retail setups, marijuana will be taxed by the state (not so in the dispensaries) and subject to rigorous testing for impurities. Where will these stores fit in to the existing markets for pot, both legal and illegal? Time will tell. 

Pricing

Pricing is an issue for any entrepreneur in any new market, and so the vexing question faces Washington State: how to price the newly legal product. If they price the product too high, customers may opt to stick with their friendly neighborhood drug dealer.

Price the product too low and the Washington's legal weed may become a player in what's known as "diversion," that is, being sold on the black market in neighboring states, sure to anger law enforcement there. Taxes on legal marijuana product will also be a boon for the state (and is one reason the ballot measure attained such high public support). 

Financing

One thing that makes budding "marijuanapreneurs" nervous is the issue of banks. Because selling marijuana remains illegal at the Federal level, growers and dispensary owners tend to keep their earnings in cash.

To circumvent this issue, entrepreneurs are looking at ancillary markets -- supplying equipment to the growers, for instance, or creating apps that rate competing products. Further, judging by the New Yorker article's profile of Kleinman, public policy consulting in states going the legalization route could be a lucrative niche for the right entrepreneur. 

Environmental Concerns 

In close-by California, high demand for medicinal marijuana has spurred large farming operations that are now threatening wildlife. Critics content that plantations in California's so called "Emerald Triangle" spill pesticides, fertilizer and other agricultural waste into waterways, according to this post on the NPR blog. Depending on local demand, Washington State could face some of the same challenges.