The Contacts Module is the second step of the sales funnel. This is where your Leads flow after the customer has "raised their hand" and expressed interest in your product or service. It has the same basic functionality as the Leads Module; however, it distinguishes the interested potential customers from unfiltered prospects.
Opportunities can be attached and weighted against contacts, and quotes can be sent to contacts. Through various levels of communication the conversion to revenue generating accounts begins at this stage in the sales funnel.
Contacts are the first step of the customer relationship building process. The lines of communication have been opened and revenue generation can begin.