An article on ThaiResidents highlights how a Thai couple got arrested this week for selling marijuana online via Facebook.
The couple (20 & 19 yo) we arrested on drug charges as they sold marijuana via comments on several Facebook pages. The police then ordered 50 grams for 2,000 THB and tracked the transaction. The bank account used for the transaction was the account of the girlfriend. As you have to show your ID card when shipping stuff around Thailand it seemed to have been rather easy to track down the couple.
The couple already admitted to all charges.
So while marijuana laws are getting less strict in regards to the medical use here, it is still illegal to sell and possess it privately! Be aware of that.