We mostly see the engagement of sellers – they are the vendors with products and services that they want us to purchase. We can pretty readily identify the seller’s agents that are involved. These include primarily the staff of the vendor itself and the sales people (which includes pre-sales engineering and any “technical” resource that gets compensation by means of the sale rather than being explicitly engaged and remunerated to represent your own interests) of the resellers (resellers being a blanket term for any company that is compensated for selling products, services or ideas that they themselves do not produce; this commonly includes value added resellers and stores.) The seller’s side is easy. Are they making money by somehow getting me to buy something? If so… seller’s agent.