Step 1: Enter name information for your contact into the fields provided, including nickname (Jeff vs Jeffery) and middle name (middle initial ok) if available.
Step 2: Enter up to three domains at which this contact is likely to have an email address.
Step 3: Click 'Permutate' and copy the resulting email addresses.
Step 4: Paste these email addresses into a Gmail email with Raportive installed, then mouse through each email address until Raportive displays social profiles for one, and Voila! You've found an active email address!
For more details see Rob Ousbey's excellent post: Find (Almost) Anyone's Email Address.