This may be a very subjective impression, but I have a suspicion that there have been two accounts created on Aviation.SE which are affiliated with a service. ProPilotNetwork and CareerPilotNetwork. In one of the answers to
Is joining the air force a good way to become an airline pilot?
The user giving the answer has referenced an external website, which does not contribute much to the answer, but to me looks like subtle advertising. I am giving the user the benefit of the doubt, since other answers met our quality requirements and have a positive vote count, but my question is:
How do we deal with subtle advertising?
Where do we draw the line?
Do we need to have this in the help centre?
I know that some answers on Aviation.SE have been created by using material from VATSIM and could this be considered precedence cases. However in these answers, the reference to VATSIM provided a contribution to the answer. I am mentioning this, since I use VATSIM for reference and material as well and don't want to sound like I was creating double standards.