Yet another reason why you shouldn't network like you're trying to sell. Every person you meet represents two or three hundred (or more) people that they are connected to. Chances are you know a portion of their contacts since we tend to run in similar circles. But most of them are going to be entirely new to you.
If you decide to network with that person, rather than sell them, you are earning their future referrals. And with a referral, you get right down to selling. They are ready for your product or service and looking to buy.
It's worth investing the time and effort to cultivate that one relationship in order to earn referrals to their network.