From the Cannabis Discussion Rules:
Prohibited use of CD
Any discussion related to drug testing
Source discussion, specifically:
soliciting or offering to provide psychoactive substances or related paraphernalia, such as:
seeds
glassware
vaporizers
grinders
scales
grow equipment
linking to domains affiliated with the sale of psychoactive substances or aforementioned paraphernalia
providing references to links in order to attempt circumventing the 'no sourcing' rule
Requests for the community to identify a substance visually