Whenever someone introduces me and my business I appreciate and try to use the opportunity. Even when I do not see a chance to do business directly with the third person I'm being introduced to, one never knows what a good impression left with this person can do in terms of future referrals. Therefore, I try to use each and every opportunity to talk about my business in a way that catches peoples' interest and creates possible future referrals.
And this is a two-way street, business people who are introduced to me can always count on me thinking about them when an opportunity shows to refer them to third parties.