If you type the numbers “420” into a Craigslist search, the site populates with scores of illegal marijuana delivery services. You get similar results by visiting Weedmaps.com, which is like Yelp for cannabis.
Under California’s legalization law, cannabis businesses must display a state license number on any public advertisement. The state of California has approved more than 4,000 marijuana businesses since Jan. 1, when the sale of recreational cannabis became legal. But many more are still operating without a license.
The state sent cease-and-desist letters to hundreds of businesses in February, telling them to get licensed or possibly face civil and criminal penalties.
Weedmaps also received a cease-and-desist letter, but the Irvine-based company refused to stop. It argues that its online marketplace isn’t subject to the same rules as the cannabis businesses that advertise there. The bureau says it went after Weedmaps because it’s the largest online marketplace for cannabis, and might crack down on Craigslist next.

“There’s a lot of business models that don’t quite work under the statute now. So I think it’s working with these businesses to see how we can get people into compliance,” said Lori Ajax, chief of the state Bureau of Cannabis Control.