OK so I'm assuming that covers direct advertising but can you be a bit more explicit on the instances where someone says "I'm looking for a wedding photographer" and someone will either reply "Use so and so...." (impersonal) or "I'm available....." (personal). The former could then be biased to photographers who use this forum but can't be mentioned hence someone else gets the job. The only fair solution I see is to stop the threads of "Spec me a Photographer.." 
