The folk hanging around to ask follow-up questions are my bet. Some of the questions really show the person is sharp enough to suggest you can put them into the

The folk hanging around to ask follow-up questions are my bet. Some of the questions really show the person is sharp enough to suggest you can put them into the system. Obviously this misses the good leads that simply don't care about your today's topic. That's in line with Google's approach being fine with a lot of false negatives.