Overview

Lead Liaison imports Salesforce.com Standard and Custom Opportunity fields. Opportunity fields are used to calculate marketing ROI, performance metrics which may be used for setting goals or distributing leads based on performance, and for automation criteria. 

...

A contact is considered linked with an opportunity when they are in the Contact Roles section of the opportunity. Opportunity criteria applies to all Contacts in the Contact Roles section. For example, suppose you had an opportunity worth $100,000 with two people in the Contact Roles section, one with a job title of VP of Sales and one as VP of Marketing. An automation using opportunity criteria of Has Opportunity with > $99,000 in revenue would select both people. However, if the criteria Job Title contains "Sales" was added with the opportunity criteria, only the VP of Sales would be selected. In summary, Lead Liaison links contacts to opportunities through the Contact Role component of an opportunity:

...

More information on Contact Roles can be found here.

Ways in Which Opportunity Data Can be Used in the System

There are many ways opportunity data can be used in Lead Liaison. Below is a short list to give you some ideas. It is not intended to be a fully exhaustive list. It's simply a short list to stimulate ideas. 

• Sending communication (handwritten letter, email, text, etc.) from the President after a deal is Closed Won
• Setting up a touch point for all Closed Lost deals with a Close Date > 1 year. How are things going? Sorry we couldn't get the relationship started...
• Notifying members of your team (internal communication) when a deal is moved to a certain status and valued above a certain amount. 
• Nurturing your customers once the opportunity moves to Closed Won with onboarding tips and tricks. 
• Sending reminders at a period (10 months, 1 year, etc.) after a deal is moved to Closed Won. 

Enabling Salesforce.com Opportunity Syncing

...