It's because of a change just made by the U.S. government, which will allow broadcasters to solicit and show advertisements for marijuana in states where the drug has been legalized. New York is one of the places where anyone over 21 can legally use the once controversial substance, which might eventually clear the way for radio and TV stations there to accept ads for it. 

It's a potentially lucrative commercial crop - it's believed it could bring in as much as $18 billion-plus in revenue if stations were willing to accept the ads. 

Exactly what they would look or sound like is altogether another thing, but you only imagine what might be coming - although I'm sure if it happens, there will be strict guidelines. Still, you can envision the difference the campaigns might sound like on a WBEN-AM (if they'd even accept them) vs. say, a WGRF-FM. 

Perhaps oldies stations WHTT or WECK could get creative and use Gary Lewis' ancient "Green Grass," Petula Clark's "The Other Man's Grass," Wilson Pickett's "Don't Let The Green Grass Fool You" or Tom Jones' "The Green, Green Grass of Home" in their campaigns. 

House Passes Bill Permitting Weed Ads on TV and Radio

As far as I know, broadcasters in Canada are not allowed to advertise the substance on stations here, though sales are currently perfectly legal. 

The one thing I'm not sure I understand is why this would be allowed, but spots for cigarettes were banned decades ago across North America for health reasons, costing stations billions in advertising. Not saying that wasn't a good thing, but I'm pretty sure smoking remains the #1 way to consume cannabis. I wonder how the tobacco companies will feel about this if it comes to be more than a "tokin" gesture.