My prospects are those people who, I believe, offer a good chance for a sale within a specific period, and that period is dependent on my business.
My prospects have to be reminded of me from time to time - perhaps every two months - and that means time and effort on my part to telephone or email them on a regular basis.
A prospect is not someone who has expressed no interest, or has expressed a very low interest in my product or services.
There's no profit to be made investing three hours a year making follow-up calls when we both know that the two-man legal firm's chances of wanting training in Application Development in VBA is close to zero.
If I have a service (monthly financial data summaries) and a product (a really cool application) and some training courses, then I'll have three marketing streams, each of which should be delivering its own stream of prospects.
And each stream should have a measured quota, and a measured result.