I'll let someone else respond to the vendor discussion portion.
The rule stems around illegal drugs but also extends to the abuse of legal drugs. For example, "dudez I just got pwned by partaking in so much legal over the counter cough syrup. Walgreens Rocks, AMIRITE?!" is not appropriate. Obviously the discussion surrounding legal drugs falls into a much greyer category; and as I am about to have shoulder surgery I could foresee an innocent conversation developing in the chatbox where painkiller usage arises.
Typically when questionable natural conversations occur in a grey area they are reviewed based on intent and impact. Across the forums the best course of action anytime something comes up that may just possibly and even slightly violate the rules or even be interpreted as a rule violation it is probably best to not say it or not participate. On the other hand, if a natural conversation develops into questionable territory (like the example above) it would be best to cease the discussion in the public venue.Originally Posted by Hypothetical Chatbox Conversation